I have very mixed feelings about this OMPL.
There were some fun times for sure. It was cool to reconnect with old friends, as well as getting to know lots of cool new people.
It was also very frustrating and infuriating at times though. Right now, I'm not sure if I'll ever participate in another team tournament (especially since OMWC didn't make the cut), but we shall see.
On a personal level, I wasn't particularly pleased with my performance. The games that I lost were VERY avoidable losses. The games I won didn't feel particularly earned either.
We did prep very well though. All but one of the games were favourable match-ups - and we won the one that wasn't.
I'd attribute my positive record largely to that if I'm honest. SV STABmons is heavily match-up dependent.
The state of the current STABmons metagame, and the lack of tiering action - in spite of it being universally agreed that there are major issues - is just disappointing. As someone who has played the meta since its debut in Generation 5 (and was on the council for a significant period). it's just sad to see how it has ended up.
I decided to commit fully to this tournament. I played a huge amount of games (probably 700+), spent many hours in the builder, and coming up with sets & strategies. The ladder experience was traumatic at times. It really isn't fun facing the same broken mons and sets over and over. Or outplaying someone only to have a certain victory stolen away by hax or skill-less moves with limited-to-no counterplay.
It has been quite frustrating to share my observations and have people that barely play tell me authoritatively that my opinions are bad. Apparently something isn't broken if they haven't personally seen it do broken things in the 20 or 30 or so games they have played/watched. Or that stuff is bad for similar reasons. I went out of my way to test multiple sets with almost every pokemon, since a lot of stuff that seemed like it would be good just struggled and stuff that seemed crap on paper turned out to be surprisingly effective.
It's no wonder the tier is in such a bad place when strong opinions seem to count more than vast experience.
I know it's not fair for me to comment on how much other people are playing - they could be grinding away in secret for all we know - but when the opinions of people who are playing the tier frequently are at odds with some of the decisions being made it can be very frustrating.
I was going to share a personal Viability Rankings to try and get the conversation started. since the current one is outdated and does not reflect the metagame at all. And also some other useful resources like the set compendium I built over the course of the tournament, and some more of the teams I built - but it doesn't feel worth it. I don't want to get flamed for claiming Archaludon is A- or Toxapex is B+, for example.
----------------------------------------------
Anyway, here's the teams I used. I don't think using them as is, is the best idea as they were mostly built with specific opponents in mind. But the general concepts and cores are probably fine with some tweaks:
Week 1:

For the first two weeks we built the teams collaboratively (thanks
betathunder ,
DeepFriedMagikarp,
Clas).
We expected to face a fairly standard Ting-Lu/Toxapex/Corviknight style balance team this week.
Betathunder suggested Mamoswine would be strong into these sorts of teams. Having watched a bunch of replays, we noticed Mamoswine was hitting 4/5 pokemon on pretty much every team super-effectively. DFM suggested Scarf Walking Wake for its strong match-up into offensive teams. It also does a good job of luring in pokemon like Toxapex, which allows us to Flip Turn into Mamoswine and get off a big hit.
Nasty Plot Rotom-W also had a strong match-up into the type of team we expected to face. With Water Shuriken legal, Rotom-W was probably one of the best mons in the entire meta actually - with strong match-ups into basically everything. A lot of Rotoms at the time were hitting 250 speed to outspeed Modest Raging Bolt, so I made mine hit 251 to speed creep them. Ice Beam was my preferred move in the last slot as it hits Water Absorb Clodsire and Raging Bolt for decent damage.
Kingambit was added to form a triple priority core with Rotom and Mamoswine. We decided to go Jolly with Low Kick since opposing Kingambit was annoying for the rest of the team
SpDef Corviknight and PhysDef Pecharunt gives us a pretty sturdy defensive backbone which is able to pivot to get Mamoswine in safely.
In the pokepaste, I've changed Rotom-W to be Steam Eruption with Sitrus Berry instead of Water Shuriken + Loaded Dice. I have no idea how effective this would be now - there's probably better options.
Week 2:

We were expecting to face some kind of Booster Energy spam Hyper Offense this week.
DFM suggested that Excadrill sand would be strong here. Our opponent didn't seem to use much Zapdos/Corviknight/Rotom-W (eg mons that give Excadrill trouble) so we decided to go for it.
In the game I decided to use Life Orb Excadrill because the extra power had been pretty convincing in some of the tests we ran, but in hindsight Soft Sand is probably the better option. You mostly end up spamming Headlong Rush and the recoil really starts to add up.
We decided that Walking Wake looked solid again. Opting for Specs this time, since we have Sand Rush Excadrill for speed.
I originally had Water Shuriken over Knock Off - since Stealth Rock and Sand chip already put Assault Vest pokemon like Toxapex into 2HKO range.
Eject Button Amoonguss was just an additional pivot to help to get Excadrill in safely. It also seemed useful for pokemon like Iron Valiant and Zamazenta. However, I don't find it that great in this meta generally - since it really struggles into a lot of pokemon, Steel types especially. Probably better being replaced with a Toxapex or something.
Pads Zamazenta with Thunderous Kick and BoltBeam coverage was chosen for its ability to bait in and weaken pokemon like Corviknight and Landorus-T so that Excadrill can sweep later on. It also provides some speed for when Sand is not active.
Week 3:


After losing to an avoidable blunder the previous week, this was the point I started really grinding out games to shake off some of my playing rust. I was also starting to feel more comfortable building my own stuff.
I think this was around the time that I realised that honest balanced teams often put you at a disadvantage (as they are too vulnerable to random cheese sets - trust me the ladder has plenty of them).
After two weeks of using bulky Walking Wake offense, it definitely felt like time to mix it up. And it's a good thing I did - since they loaded 3 water types (including Primarina).
I'd originally been playing around with a bulky team with multiple Salt Cure users, and at some point it kind of morphed into a full stall team.
As far as stall goes in this meta, I think this is a pretty decent build that manages to cover most of the major threats well. Obviously, stallbreakers like Thundurus-T and Hoopa-U can still be problematic. And it's possible to get overwhelmed or lose a key piece to hax.
The Corviknight can be a standard Rocky Helmet PhysDef set to act as a more stanard Knock Off absorber. I decided to use the SpDef Covert Cloak set though, since I appreciated having a mixed wall that can pivot. It also gives you a decent mid-ground for certain mons like Gholdengo and Latios - if you don't want to risk Blissey getting tricked.
Tyranitar's Knock Off as the only item removal is also not ideal - so Corrosive Gas can be considered on Pecharunt or Clodsire.
Week 4:

Slither Wing caught my attention as a pokemon with unexplored potential in the metagame. Since we were facing Time2Bonk's team (and they had just changed their Smogon username from Slither Wing), it seemed like the ideal time to use it.
A Protective Pads pivot set with Thunderous Kick seemed really good. Thunderous Kick into Earthquake/Wild Charge managed to KO many of the common switch-ins. Originally I wanted to use Will-O-Wisp to annoy walls like Corviknight and Landorus-T, but First Impression ended up being a better fit.
I figured a bulky Volt Turn style team would allow me to make the most out of Slither Wing's strengths. Part way through building the team, I realised it looked a lot like a team that I'd seen VolcanionIsGood using - Except with Slither Wing in the place of his Infernape - so I decided to commit to that fully.
Week 5:

This was the week that Combat Torque and Water Shuriken got banned. I decided to go with full on HO to take advantage of the bans - and it looks like I wasn't the only one to have that idea.
Looking at some early SV OU teams, the idea of Annihilape and Volcarona behind screens seemed like it could be very powerful.
This team went through a bunch of iterations. Originally it was Deoxys-S setting the Screens. I tried lots of different set-up pokemon too.
Eg, Stored Power Latias, Blaziken (special and physical), SD Samurott-H, CM Sylveon, SD Kingambit.
At some point I realised that half my team was freed uber pokemon, and then remembered that Regieleki could set Screens. The idea of using only Ubers (with little regard for synergy or defensive typing) on the week stuff had finally got banned just seemed kind of funny to me, so I ran with it.
Despite not much thought going into the team, it has been surprisingly effective. If one guy can't set up and sweep, another usually can.
Archaludon can be replaced with Kingambit if priority is required.
And Espathra can run Colbur Berry + Roost instead of Leftovers + Protect.
Max Speed Regieleki outspeeds Booster Speed Iron Valiant and can Nuzzle it.
Week 6:

I had toyed around with the idea of Psychic Terrain offense earlier in the tour, but decided against it due to its inconsistency.
However, after facing it randomly on the ladder, I decided it could be worse re-exploring.
These kinds of teams typically rely on Magic Bounce Hatterene to deflect hazards and keep the multiple Focus Sashes intact. However, after a lot of testing, I found Hatterene to be pretty useless at preventing hazards in this metagame. Stone Axe is reasonably common for starters. And Also Hatterene's bulk struggles to keep up with the increased power level. It's a shame really, since that pokemon has a lot of interesting qualities.
Instead I decided that I would try and fit other removal options onto my non-sashed pokemon.
I originally had Court Change Indeedee, but decided I'd rather play with no hazards at all.
Mortal Spin Iron Moth is a pokemon I'd used on other HO teams. Being able to threaten steel types who might try and block the spin is very useful. Psychic Terrain also helps cover its main weakness in STABmons (priority).
I had noticed that my opponents didn't tend to use many Rocky Helmets so I decided to take advantage and use Population Bomb Ambipom. A very strong and powerful pokemon, but weak to priority and Rocky Helmets (which were not an issue here).
Being able to Tidy Up also helps with the hazards/Focus Sash preservation issue.
Psychic Terrain Sash Spam is always going to be a fishy team to bring. I'd made a list of the main 5 pokemon that I definitely did not want to see when using this team - and they brought 3 of them.... (Rillaboom, Heatran, Stone Axe Ogerpon-C)
Week 7:

The game this week ended up not happening. But since it already didn't matter towards the playoffs, we were planning on bringing a fun team.
Basically a STABmons version of the infamous Mono Claw team.
It actually performed surprisingly well in tests - and went about 17-3 on the ladder.
I'd considered one of the previous weeks actually, but then I chickened out due to the major ground weakness.
Seriously, Landorus-T, Mamoswine, Excadrill can basically all 6-0 if the claw does not activate - and there's no Tera here to get out of it.
Semi-Finals:

Since the unbanning of Manaphy and Araquanid, rain gained two very powerful tools. It's no coincidence that it is suddenly being spammed everywhere on the ladder after being rarely seen at all for a very long time.
There were a few different versions of this team.
It's mainly the Basculegion slot that changes (either for Basculegion-F, Barraskewda, Thundurus, Thundurus-T).
I got scared of facing a Meloetta and decided to bring this version - despite it being pretty much worse than the others.
The game itself ended up being very weird.
Ended up facing a team very weak to Araquanid (and kind of soft into Archaludon and Pelipper too).
-------
I ended up making a lot more teams over the course of the tournament - might post some of the more useable ones later, but I'm not sure.
I found it interesting that I didn't use pokemon like Landorus-T, Heatran, and Slowking a single time - despite them being on a lot of my teams in previous generations. But as I said before, loading cheesier stuff seems to be the optimal way to play such a volatile metagame with so many broken elements flying around.