Also, just look at the set on the signature of raikoulover; you are saying that tornadus-t should be banned because it has no counters, lol then tell me a counter for that Salamence. Seriously if you find one thing that can counter it then ill vote tornadus uber.
Unfortunately, something like max Def eviolite chansey probably works...but that's really irrelevant lol. A good example though--SpDrachi shuts down tornadus way more easily than anything does to that mence set (and imagine if that set got a moxie boost? I doubt there's anything that isn't 2HKOed).
The point here that seems to be coming up a lot is that torny can wear down its counters by using u-turn. Well, this is 100% not true for rachi--run wish + protect if you must, both moves are viable for other stuff. I guarantee that that set will not fail to come in on torny as many times throughout the match as you want and wall it for days (assuming no ridiculous hax).
The wearing down notion does have bearing though on the other proposed counters--rotom-w for example. It just so happens that tom was not given a reliable healing move, so it is thus unable to come in on torny repeatedly throughout the match without losing health in the process. OK, so this is
not a foolproof counter to torny, but it is a poke that can reliably come into any move and threaten heavy damage multiple times throughout a match. It also has pain split which, while not the most reliable healing move, helps its survivability, and it can run a great chestoresto set as well.
Then what about stuff like SpD skarmory? It can easily live 2 hurricanes after rocks and roost back up. If the opponent taunts, they a) must not be speced, meaning you're taking a lot less damage, and b) are risking the predicted BB and subsequent ~40% lost, a 2HKO after rocks or a couple rounds of LO. And then, skarmory can just come in on one of the many things that it hard-walls--in rain, basically every physical dragon to start with--and recover any health lost in that encounter.
So what's my conclusion? Well, I could still probably be swayed at this point, but it seems to me like this: torny has at least 1 ABSOLUTE counter in SpDrachi, and many good checks such as rotom-w, SpD skarm, heck, any SpD steel in rain not weak to fighting does ok. No, these pokes cannot come on torny an infinite number of times without losing health, but they can come in on any attack and have an advantageous matchup. Honestly, something like bandkion is much harder to switch into without losing health each time--say you send in gliscor, one of the best terra checks, vs bandkion. You don't have PH activated yet, so you take 12% from rocks, ~45% from SE, and are left at 37% with toxic orb now activated. You use protect to live the next SE as they switch to any poke with an ice move. Now you're at 50%. Even if you protect again, you're leaving the field with 62%, which will be 50% on your next switch-in--how are you going to take another hit from terra?
Anyway, as I said, I'm not completely decided yet, but I just don't think I see what makes torny so much harder to check than other top-tier offensive OU pokes.
Oh, and I really don't see what keldeo has that makes it even possibly broken at all. Like literally, what does it have over terrakion? Possible double STAB on hpump, good partnering with ttar, and...that's about it. And in return, terra gets unresisted STAB, a set-up move that doubles his primary offensive stat, a potential SpD boost from SS, a speed-boosting move, SR and taunt, and more. terra can run something like ten viable sets (band, scarf, SRlead, subSD rock gem, subsalac, subliechi rock polish, double dance, LO SD, even bulky double dance is viable and there are probably more). Keldeo has like scarf, specs, CM, and subCM, and gets walled by so much more. Don't see the argument for this one.