First XY OU team, please rate

[Third]

Hey everyone, please help me with with making this team. I wanted to lean more towards a balanced sort of team than a hyper offensive or stall team. Warning, it's a pretty long read.

Lucario (M) @ Lucarionite
Ability: Justified
EVs: 4 Def / 252 Atk / 252 Spd
Jolly Nature
- Swords Dance
- Close Combat
- Crunch
- Bullet Punch

Lucario's one of my favorite Pokemon, and I was ecstatic when it got a mega evolution this generation. I wanted to be able to use it and it's mostly my set up physical sweeper. Swords dance boosts its 145 base attack to ridiculous levels, and Justified is so that I can switch into a Knock Off or something and get an attack raise without needing to Swords Dance.

Genesect @ Choice Scarf
Ability: Download
EVs: 252 Atk / 252 Spd / 4 SAtk
Naive Nature
- U-turn
- Ice Beam
- Explosion
- Iron Head

Genesect is an excellent Pokemon for keeping momentum as well as being able to dish out a lot of damage with STAB potentially +1 U-turn. Also, it outspeeds Greninja and can OHKO Mamoswine, which gives the rest of my team a problem. It can also revenge kill many different Pokemon in case Lucario's Bullet Punch isn't good enough.

Latios (M) @ Life Orb
Ability: Levitate
EVs: 252 Spd / 252 SAtk / 4 HP
Timid Nature
- Draco Meteor
- Psyshock
- Surf
- Roost

I didn't want to completely rely on physical attacks on my team, as a physical wall or a burn could break it apart easily. Latios was perfect because it has immense special attack and outspeeds a lot of Pokemon. I chose Roost over Defog because I already have a Defogger on my team, so having two would be a little overkill.

Heatran (F) @ Leftovers
Ability: Flash Fire
EVs: 248 HP / 8 Def / 252 SDef
Calm Nature
- Stealth Rock
- Lava Plume
- Protect
- Roar

Now that the attackers have been set, I wanted a wall that could set up rocks so it'll break Sturdy or Focus Sashes that could otherwise prevent sweeps with Lucario, as well as wall a lot of special attackers. I've used Heatran before and it rarely lets me down as a special wall, as its typing gives it immunity to Toxic and its ability gives it immunity to fire. It's also a good wall for Talonflame, which I see everywhere now.

Mandibuzz (F) @ Leftovers
Ability: Overcoat
EVs: 248 HP / 216 Def / 44 SDef
Bold Nature
- Defog
- Foul Play
- Taunt
- Roost

I looked back at the other members of my team and thought that I should get a strong defensive wall. Mandibuzz seemed like the best choice, because it not only has great stats for being a physical wall, it gets rid of entry hazards, though at the same time it also gets rid of my hazards. I could work around this by defogging entry hazards after their set up is done and bring in Heatran to set up rocks.

Trevenant (F) @ Sitrus Berry
Ability: Harvest
EVs: 248 HP / 76 Def / 184 SDef
Careful Nature
- Will-O-Wisp
- Leech Seed
- Substitute
- Curse

Finally, I saw that one Pokemon could pretty much break this team apart: Rotom-W. I do have the special wall that is Heatran, but it can only take so many Hydro Pumps before it faints. I know predicting well would help with Rotom-W, but nothing's really able to come in on it. So I put Trevenant as another wall. It's a special wall, because I have enough faith in the abilities of Mandibuzz as well as the other to take physical hits enough. I have Will-O-Wisp to burn opposing physical attackers and Leech Seed to annoy others. Sitrus Berry over Lum Berry because I truly doubt I'll get many status conditions, especially if I'm already behind a Substitute. Plus, Trevenant is a very versatile Pokemon in general, so it could take hits from mostly anything.

I feel like my team is pretty solid in terms of covering for each other and being able to dish out a lot of damage too, but I feel like it's also missing something. Maybe it's the EV spreads or bad play on my part, or maybe one of the 718 Pokemon could do something to my team. Either way, I still feel like I'm missing something, and I need you guys to help me out by rating it. I would greatly appreciate it if you took your time to explain what kinds of problems my team has and how to improve it, but a simple rate would also work fine. Thanks in advance.

 

[aPandaCub]

You don't have anything to counter Greninja, unless Hydro Pump misses on Lucario or you get a dragon dance up with Salamence.

Your team also has a serious weakness to Sash Mamoswine, which pretty much can handle 5 out of 6 of your team.

I would suggest a Chesto-Rest with Harvest Trevenant. Or the infamous Curse Harvest Trevenant, which is one of the most annoying mons besides klefki.

I would suggest Outrage over Dragon Claw on Salamence. You're missing out on some vital KOs with it, and Lum Berry would snap you out of confusion regardless.

 

[Third]

Based on what you said, I think Rotom-W would do well against both, because with Greninja, it can take anything from it. Same thing with Mamoswine. Though what Pokemon should I replace if I put Rotom-W on my team?
I've tried out Curse Harvest Trevenant before, and it worked out well for me. Which move do you think I should get rid of for Curse? Leech Seed?

 

[aPandaCub]

Try running Curse over Shadow Claw. Then spread the EVs to make Trevenant as bulky as possible.

You could also just throw a Choice Scarf on Salamence and have it be your revenge killer. That also works great as a late game cleaner as you accumulate moxie boosts. To deal with Mamoswine, you could try to break its sash then outspeed and kill with Lucario.

Or you can replace Salamence with a physically scarfed Genesect, which has U Turn to kill Greninja, and Iron Head to kill Mamoswine.

 

[Third]

I've replaced Salamence with this set of Genesect and I also got rid of Shadow Claw on Trevenant.

Genesect @ Choice Scarf
Ability: Download
EVs: 252 Atk / 252 Spd / 4 SAtk
Naive Nature
- U-turn
- Ice Beam
- Explosion
- Iron Head

Thanks for the help, anything else that could be improved?

 

[Oranos]

I strongly recommend running extreme speed on lucario over crunch. You have dark coverage on greninja and the +2 priority will allow you to beat the massive amount of +1 priority moves running around this gen (Extreme speed will take priority over other priority moves such as bullet punch, if you weren't aware). If you get off a swords dance boost, extreme speed packs a surprising punch, and will take down pokemon that it would otherwise never be able to face such as talonflame (assuming some prior damage)

 

[Third]

That's true, but I think Mega Lucario's speed is enough to outspeed most of the attacks in the same priority bracket. I like to keep Crunch because in case something like Aegislash or another bulky ghost type switches in, I don't have to switch out, giving them a turn of setting up and potentially sweeping. For Talonflame, I have Tyranitar and Gliscor to an extent to take damage and then proceed to kill it.