Ok, I've used this team for quite some time. I'm a bit new around here and competitive battling was just something I recently got into in the past months.
Bait/Special Sweeper
Yanmega @ Focus Sash
Ability: Speed Boost
EVs: 252 Special Attack/252 Speed/4 Attack
Modest Nature (+Special Attack, -Attack)
Bug Buzz
Air Slash
U-Turn
Protect
I already know my U-Turn is hindered by the -Attack, but I really didn't have much other ideas of what nature to give it based on the rest of my team. I also originally had Hypnosis on this, but have taken it off since Hypnosis got lowered to 60% Accuracy in Platinum and it wasn't very reliable to begin with.This is one member that I've been questioning lately. I generally use this one as my lead and as bait. Yanmega is bait, with a bit of out-prediction, I can use Protect to scout one of my opponent's moves, although it's something I don't generally use on the first turn due to them trying to setup on me.
Now, what I mean by Yanmega being "bait" is that often times if someone isn't prepared to fight it, they will switch out giving me a chance to hit them once upon them switching, get a Speed Boost, then U-Turn them and go to my other members which I've chosen to have mostly immunities and high resistances to all of Yanmega's weaknesses. If they don't take the bait, Yanmega gets a guaranteed free hit that it can take and now they now have a sped-up Special sweeper on thier hands.
It's a good setup, but it won't work against the same foe twice in some cases.
Physical Sweeper/Tank
Metagross @ Choice Scarf
Ability: Clear Body
EVs: 132 Speed/252 Attack/124 HP
Adamant Nature
Meteor Mash
ThunderPunch
Earthquake
Explosion
This is usually what I go to if someone pulls out Rock Type or even an Ice Type against Yanmega. He's great at walling just about anything, the Choice Scarf was something I encountered in battle once and liked the idea a lot, so I made my own build around it. It will out-speed quite a bit with a 1.5x speed boost, at least most things. For those that it doesn't, like Weavile, it can wall most of them. Then at last, he is disposable with Explosion if I need a quick KO to finish something off, but I can usually be sure that he'll take out one or two Pokémon every time before needing to resort to it.
Mixed Attacker
Flygon @ Life Orb
80 HP/252 Attack/176 Speed
Ability: Levitate
Hasty Nature (+Speed, -Defense)
Dragon Claw
Earthquake
Draco Meteor
Roost
This one is fairly easy to get going. Switch in whenever I have something weak to ground out like Metagross or whenever someone sends out a Fire or Electric Type on my lead, I can go straight to Flygon. The -Defense Nature makes it not as useful against switching in on Rock Types as it could be, but it's worked better for me with special Ice moves as well as Dragon Pulse. Most things people switch into to counter Flygon have low Special Defense which is why I have Draco Meteor in there since Flygon has at least decent Special Attack and gets STAB with Draco Meteor.
Earthquake and Dragon Claw are obvious, I was considering Outrage since I have Platinum, but with Life Orb it isn't the better choice. Speaking of my Life Orb, that's where Roost comes in. If I switch it out and then choose to use it again later, I can heal off the damage from it in most cases if I can predict a switch.
My biggest weakness here is Weavile, but as I've mentioned before, Metagross does great against walling it should I need to switch and I won't have to worry as much if I'm not stuck in an Outrage. This Flygon was meant to replace my Garchomp when I couldn't use him any more in OU and I think it proves a bit more valuable to the team in the end.
Physical Wall
Weezing @ Black Sludge
Ability: Levitate
EVs: 252 HP/252 Defense/4 Special Attack
Bold Nature (+Defense, -Attack)
Flamethrower
Thunder
Pain Split
Will-o-Wisp
A pretty typical build fo a Weezing, but I like it. He gives me another Ground immunity incase Flygon fails which is great with how common Ground is. The only one weakness to Psychic is really good to have and it overall can rip almost anything Physical apart. I assume anyone around here knows the amazing defensive power of a Weezing, so I won't need to go too far into this since it's been heard before. I personally think Weezing is pretty under-rated these days mainly due to the Physical/Special split of Diamond & Pearl, while it weakened him ever so slightly in offensive power, he's still a very valuable addition. His ability to resist Fighting Physical Attackers on a ridiculous scale now brings me to what else I use him to switch-in for...
Annoyer/Support
Blissey @ Lum Berry
Ability: Natural Cure
EVs: 252 Defense/216 Special Defense/40 Special Attack
Thunder Wave
Stealth Rock
Ice Beam
Softboiled
If this gets going, work will be much easier for the rest of my team and there's an infinite number of things I can switch into special walling. It's another option should Yanmega get used again and my switch-ins for it have since fallen. I usually like to get this one into the field at least once due to Stealth Rock, for obvious reason. It's also really nice for stopping things dead in their tracks, setting up, and then recovering off damage. She's as effective as ever, but I'm looking into whether or not I could use a better hold item. It's usually just there if something tries to put it to sleep or freezes me and I'm not done setting up yet.
Support/Tank
Umbreon @ Leftovers
Ability: Synchronize
EVs: 252 HP/200 Attack/56 Special Defense
Sassy Nature (-Speed, +Special Defense)
Curse
Wish
Payback
Baton Pass
Umbreon is good in many situations, for being a good switch-in if Weezing runs into trouble agaisnt a Psychic Special Attacker, good for being a back-up to other Physicak attackers, getting a nice setup to use Payback after one or two Curses.
This is, however, one I have questions about. I realize that a lot of my team is based around Speed, save for Blissey who would only benefit from the +Defense which it dearly needs to take a hit in a tight spot. But even so, this is making me question my Curse Pass almost entirely. It's a really effective build, just maybe not as inclined for my team as it could be. I'm open to all suggestions on something I could put in its place.
Closing notes
I've played with this team for a while now. I've battled competitive players quite a few times in the recent months before choosing to join Smogon after lurking for a long time, but I'm wondering if it's time for a change. I used to love using this team, but lately I've found myself a lot more unsure of it. The two biggest Pokémon I am questioning are Umbreon and Yanmega, so I'm open to any suggestions or alternatives here. This team mainly emphasizes on speed, even with its bulkier members which is why I'm not sure if Umbreon as a Curse-passer fits in. I think that right there is my biggest weak point and I'd like to know what I could do to change it.
Overall, I've been having a lot of fun so far with people I've battled on a competitive level and I'd like to learn more and get into battling more if I could get second opinions from more experienced people. I also apologize if this post wasn't very good, I tried my best at writing it for a first timer at a Rate My Team thread after reading through various other ones.
Anyway, thank you for your time reading this post and I hope to hear what you all have to say on it whether it be good or bad.
Bait/Special Sweeper

Yanmega @ Focus Sash
Ability: Speed Boost
EVs: 252 Special Attack/252 Speed/4 Attack
Modest Nature (+Special Attack, -Attack)
Bug Buzz
Air Slash
U-Turn
Protect
I already know my U-Turn is hindered by the -Attack, but I really didn't have much other ideas of what nature to give it based on the rest of my team. I also originally had Hypnosis on this, but have taken it off since Hypnosis got lowered to 60% Accuracy in Platinum and it wasn't very reliable to begin with.This is one member that I've been questioning lately. I generally use this one as my lead and as bait. Yanmega is bait, with a bit of out-prediction, I can use Protect to scout one of my opponent's moves, although it's something I don't generally use on the first turn due to them trying to setup on me.
Now, what I mean by Yanmega being "bait" is that often times if someone isn't prepared to fight it, they will switch out giving me a chance to hit them once upon them switching, get a Speed Boost, then U-Turn them and go to my other members which I've chosen to have mostly immunities and high resistances to all of Yanmega's weaknesses. If they don't take the bait, Yanmega gets a guaranteed free hit that it can take and now they now have a sped-up Special sweeper on thier hands.
It's a good setup, but it won't work against the same foe twice in some cases.
Physical Sweeper/Tank

Metagross @ Choice Scarf
Ability: Clear Body
EVs: 132 Speed/252 Attack/124 HP
Adamant Nature
Meteor Mash
ThunderPunch
Earthquake
Explosion
This is usually what I go to if someone pulls out Rock Type or even an Ice Type against Yanmega. He's great at walling just about anything, the Choice Scarf was something I encountered in battle once and liked the idea a lot, so I made my own build around it. It will out-speed quite a bit with a 1.5x speed boost, at least most things. For those that it doesn't, like Weavile, it can wall most of them. Then at last, he is disposable with Explosion if I need a quick KO to finish something off, but I can usually be sure that he'll take out one or two Pokémon every time before needing to resort to it.
Mixed Attacker

Flygon @ Life Orb
80 HP/252 Attack/176 Speed
Ability: Levitate
Hasty Nature (+Speed, -Defense)
Dragon Claw
Earthquake
Draco Meteor
Roost
This one is fairly easy to get going. Switch in whenever I have something weak to ground out like Metagross or whenever someone sends out a Fire or Electric Type on my lead, I can go straight to Flygon. The -Defense Nature makes it not as useful against switching in on Rock Types as it could be, but it's worked better for me with special Ice moves as well as Dragon Pulse. Most things people switch into to counter Flygon have low Special Defense which is why I have Draco Meteor in there since Flygon has at least decent Special Attack and gets STAB with Draco Meteor.
Earthquake and Dragon Claw are obvious, I was considering Outrage since I have Platinum, but with Life Orb it isn't the better choice. Speaking of my Life Orb, that's where Roost comes in. If I switch it out and then choose to use it again later, I can heal off the damage from it in most cases if I can predict a switch.
My biggest weakness here is Weavile, but as I've mentioned before, Metagross does great against walling it should I need to switch and I won't have to worry as much if I'm not stuck in an Outrage. This Flygon was meant to replace my Garchomp when I couldn't use him any more in OU and I think it proves a bit more valuable to the team in the end.
Physical Wall

Weezing @ Black Sludge
Ability: Levitate
EVs: 252 HP/252 Defense/4 Special Attack
Bold Nature (+Defense, -Attack)
Flamethrower
Thunder
Pain Split
Will-o-Wisp
A pretty typical build fo a Weezing, but I like it. He gives me another Ground immunity incase Flygon fails which is great with how common Ground is. The only one weakness to Psychic is really good to have and it overall can rip almost anything Physical apart. I assume anyone around here knows the amazing defensive power of a Weezing, so I won't need to go too far into this since it's been heard before. I personally think Weezing is pretty under-rated these days mainly due to the Physical/Special split of Diamond & Pearl, while it weakened him ever so slightly in offensive power, he's still a very valuable addition. His ability to resist Fighting Physical Attackers on a ridiculous scale now brings me to what else I use him to switch-in for...
Annoyer/Support

Blissey @ Lum Berry
Ability: Natural Cure
EVs: 252 Defense/216 Special Defense/40 Special Attack
Thunder Wave
Stealth Rock
Ice Beam
Softboiled
If this gets going, work will be much easier for the rest of my team and there's an infinite number of things I can switch into special walling. It's another option should Yanmega get used again and my switch-ins for it have since fallen. I usually like to get this one into the field at least once due to Stealth Rock, for obvious reason. It's also really nice for stopping things dead in their tracks, setting up, and then recovering off damage. She's as effective as ever, but I'm looking into whether or not I could use a better hold item. It's usually just there if something tries to put it to sleep or freezes me and I'm not done setting up yet.
Support/Tank

Umbreon @ Leftovers
Ability: Synchronize
EVs: 252 HP/200 Attack/56 Special Defense
Sassy Nature (-Speed, +Special Defense)
Curse
Wish
Payback
Baton Pass
Umbreon is good in many situations, for being a good switch-in if Weezing runs into trouble agaisnt a Psychic Special Attacker, good for being a back-up to other Physicak attackers, getting a nice setup to use Payback after one or two Curses.
This is, however, one I have questions about. I realize that a lot of my team is based around Speed, save for Blissey who would only benefit from the +Defense which it dearly needs to take a hit in a tight spot. But even so, this is making me question my Curse Pass almost entirely. It's a really effective build, just maybe not as inclined for my team as it could be. I'm open to all suggestions on something I could put in its place.
Closing notes
I've played with this team for a while now. I've battled competitive players quite a few times in the recent months before choosing to join Smogon after lurking for a long time, but I'm wondering if it's time for a change. I used to love using this team, but lately I've found myself a lot more unsure of it. The two biggest Pokémon I am questioning are Umbreon and Yanmega, so I'm open to any suggestions or alternatives here. This team mainly emphasizes on speed, even with its bulkier members which is why I'm not sure if Umbreon as a Curse-passer fits in. I think that right there is my biggest weak point and I'd like to know what I could do to change it.
Overall, I've been having a lot of fun so far with people I've battled on a competitive level and I'd like to learn more and get into battling more if I could get second opinions from more experienced people. I also apologize if this post wasn't very good, I tried my best at writing it for a first timer at a Rate My Team thread after reading through various other ones.
Anyway, thank you for your time reading this post and I hope to hear what you all have to say on it whether it be good or bad.