Kay, I think I should talk a little bit about Genesect, cuz i used it a lot when it was allowed and was really happy that it was available in round 1 and used it in all 3 games. Now, I know that its most popular set was scarf, but i never liked it cuz it could not revenge +1 zard-x. i will mainly talk about the rock polish set. Its typing allows it to set up on a lot of pokemon (fairies as they can't risk a potential iron head, latis especially if they have dracoed, scizor etc.). It has got an immense movepool. Fire, Ice, Electric coverage is fantastic. Just take care of Heatran and other fire types and you are good to go. And, its not that tough to do so given the number of water types and Heatran's lack of recovery and hazards. I used Giga drain instead of Thunderbolt as it still hits water types and negates LO recoil and yeah it came in handy. However, as much as i love using this monster, I really don't think it has any place in OU. It has 124756978458522409 sets and can be using any one of those and there is one universal counter Heatran. Rock Polish, shift gear, cb, physical scarf, special scarf and a lot of move combos possible. This thing is not like mega mawile having huge power (hehehe) but it is a momentum machine that can run a lot of sets. Just keep it outta OU.
You make some valid points that I agree with, but a couple of them seem a little overstated.
First, I would say that Genesect does have good typing but only "good enough" bulk; it's purpose isn't to actually come in and sponge hits but rather act as a hit-and-runner. Sure, maybe it can take a LO Draco Meteor but only once, and at what cost? Now it has to play very conservatively (especially with u-turn) the rest of the match against any of OU's common rocky helmet users, or more selectively decide when it comes into play on hazards, other weak attacks, etc. In an actual battle and in most of the replays, it was usually Genesect absorbing u-turns from opposing Gene, with maybe a couple of correct predictions on an ice beam / tbolt / etc.
Second, its versatility in movepool and number of sets (I group those points together) lends weight to both supporters and opposition of Genesect, I'll try my best to explain why. Those who are against Gene make the case, like you have, that "because it has access to so many different coverage options and boosting capabilities, you can't
reasonably determine which set your opponent is running. Further, because you can't know the set your opponent is running, Genesect can either bluff having certain coverage, have certain coverage and get KOs, or u-turn out on expected coverage to preserve momentum."
Let me illustrate the other side, though, and hopefully you'll see where I'm coming from (since I don't want to assume I necessarily speak for all people who are somewhat interested in a retest). Let's say you bring Genesect and I brought stall, and I lead off with Mega Sableye and you lead with Genesect. In my opinion this is actually a difficult scenario for the Genesect user because
the minute you click any move, you have just revealed a ton of information about your set, right from turn 1. If you're the Choice Scarf + U-turn + IB/FT/TBolt set, that means you aren't going to be running any (or hardly any) EVs in attack as you've chosen to specialize your Genesect as a special attacker. So if you click U-turn, given the EV spread and the set I've suggested, you're going to be doing somewhere between 17-20% based on rolls and/or Timid vs Hasty nature. The Sableye user is free to simply click recover, and now knows "okay, this Genesect definitely isn't Choice Banded, which would have done 27-32%, and almost certainly means it doesn't have Extreme Speed". You could even go further and say "now I know that X or Y pokemon will be able to check Genesect throughout the rest of the match given that it's this set instead of another one". You could also assume that it's running Ice Beam and Flamethrower but some people aren't comfortable doing that, which is fine, they don't have to. Even in the worst case scenario, it's Life Orb Genesect with Bug Buzz at +1 SpA; Sableye still recovers to over half and knows that any of stall's dedicated special walls can check/counter it.
But let's say you don't like that example, don't play stall or think I cherry-picked something easy to explain. Let's take a very common lead-matchup example on Balance instead: Genesect vs TankChomp. Automatically you're inclined to think "this must be a really bad matchup for the Garchomp user, since Genesect could have Ice Beam and they'll lose Garchomp turn 1!". Let's take a step back and analyze what's really happening here, though. Genesect can either 1) Click Ice Beam, attempting to kill the Garchomp, 2) Click u-turn, expecting the Garchomp to switch and preserve momentum, or 3) Click a different coverage move in an attempt to predict what the Garchomp user might switch out into. I suppose option #4 could be "Genesect hard switches-out", as well, but I assume that was a given.
Realistically, though, what are the costs vs benefits of each of those options?:
Option 1: Ice Beam
Cost - If they switch out expecting the Ice Beam, you have just lost momentum and revealed a lot about your set. Not ideal.
Benefit - If they stay in, you kill Garchomp! Hurray!
Option 2: U-turn
Cost - If they stay in, you take Rough Skin + Rocky Helmet damage, you've predicted wrong and the Chomp user has the advantage. Staying in means they're getting a free SR, EQ or whatever other move they clicked, but likely SR if they've purposely chosen to stay in and predict your switch. You get off very poor damage on Chomp with U-turn in exchange for more damage in return, and you've arguably just lost momentum (and/or conceded SR).
Benefit - If your opponent switches out expecting the Ice Beam and you don't want to make an aggressive play, you can u-turn, which gives you momentum.
Option 3: Click [coverage move] expecting [Ice Beam check]
Cost - If Garchomp stays in, you just selected a very poor move, have lost a lot of momentum now Genesect is still in play, and must switch out next turn or take a Fire Blast/EQ/etc.
Benefit - This is extremely subjective. It requires you to make an aggressive play turn 1. It also requires you to accurately predict the exact switch-in your opponent will choose. If the choice is between Ferrothorn or Manaphy, what do you pick? But the benefit is that if you manage to navigate this head-game correctly, you might possibly get a KO on whatever comes in.
Option 4: Hard-switch out into something favorable vs TankChomp, or make an aggressive
switch (rather than an aggressive
move) like Option 3.
Cost - If Chomp stays in, you missed an opportunity to KO, may have conceded SR or might take an un-invested EQ.
Benefit - You don't reveal your set, you take no residual damage, and either you guessed their switch right or you both switched and you've not lost any ground.
I already know that for some players, they've stopped reading because to them, this is too much going on and they'll write it off (a la Aegislash) as "excessive 50/50s dude!". However what I'm hoping to illustrate here is that this isn't a "50/50" at all. Literally, "50/50" means "A player has an equal chance of making move A or move B and you can't possibly know, beyond guessing, which one they'll choose because move A and move B have
equal utility". Looking at the options Genesect has above, first off, there are 4 options so if you like calling it a "25/25/25/25" then that's fine. However even that isn't really true, because you just made every option have an equal probability, and an insightful player will quickly realize that none of these options are equally valuable for the Genesect user without bearing a relevant cost. In fact, not only are all the options not equal in utility for the Gene user, but some of them are not great options at all (hence the reluctance of players to make aggressive plays, especially on turn 1). The best possible option as far as potential benefits exceeding potential costs is actually to just hard-switch out, aka Option 4. Some people would prefer to just click Ice Beam (option 1) and play it safely, but you do so with the knowledge that your opponent can take advantage of this situation and put you in a bad position (if they switched into Manaphy, as one example). Going for u-turn is a viable option (#2) only if they do switch out, only if you are actually a set that carries Ice Beam and only if your opponent doesn't recognize that you have the freedom to make that play (in other words, they make a move as aggressively as you do).
I don't think this turns the game into a prediction war or unreasonably "warps" the battle around Genesect. To me, this simply raises the level of skill required to win or outplay your opponent, which is a desirable aspect of any competitive game. It can't always be a battle of "1 star" plays, where everything has a hard counter and you know all your opponent's sets. Sometimes you're going to be in situations where you aren't going to know what your opponent will do (or what they're running) but will have to make a play based on your best odds of success. That's what this game is all about, managing your odds and risk vs reward, and I don't think Genesect (at this point in time) exacerbates this problem to an unhealthy extent.
Open to changing my mind, though. Sorry for the wall of text, got carried away.