I'll say Garchomp, and here's some reasoning. Both positive and negative!
First, I don't see him being a prominent setup sweeper that takes entire teams down. The most commonly seen Garchomps will probably be the scarfed versions. Revenge killers. Dang good revenge killers and harder to take down, but still. The only version that could be a deadly setup sweeper is the sub/dd version that the above poster mentioned. And it can be phazed, something most teams carry anyway.
Secondly, a lot of the metagame has been centralizing around Dragonite, much more so than before. Seriously, everyone's prepared for Dragonite. I've been seeing a TON of Mammoswine and Scizor lately. Since that's the direction the metagame is headed in, I feel a lot of teams are a lot more prepared for Garchomp than they think they are. Ice Shard and Bullet Punch! Not OHKOs, but they'll put a dent into Garchomp, and he can be worn out throughout the match like any revenge killer. Priority moves aside, the main thing that flat-out outspeeds Garchomp is a scarfed Latios. That became something we just didn't see for a while, but with the emergence of Dragonite, Haxorus, and even Salamence, I've been seeing it lately! This stuff that checks Garchomp isn't a wasted teamslot that prepares you for him only... it's stuff that's already being carried on teams to prepare for the metagame as it is.
The weather was one of the reasons people say they favor Garchomp being banned. Hitting him in the sand is tough and a miss can be game-changing. But with how popular weather is, Garchomp is plenty likely to end up under the rain, sun, or even hail. (I've seen way more hail teams lately... anyone else?) Plenty of "weather wars" as we call them tend to come down to who wins the weather setting battle. How is Garchomp's evasion that much of an exception?
Now... this is a different subject that I won't go into that deeply... but... If Sand Veil really is the last thing pushing him over the edge... There could always be discussion for a "no sand stream + sand veil on the same team" ban. I don't see that as a partial ban of a poke. It's no different from drizzle/ss. Drizzle isn't banned, nor is ss. You just can't have them on the same team. Back to the subject...
The things I see going against Garchomp are the same as always. Yep, he's got those huge stats. He's tough to take down. But it can be done. He's not weak to SR like Dragonite and Salamence. Yep, but those 2 fly and are immune to spikes, where Garchomp is not. Garchomp is immune to the priority Thunder Wave of the now-unbanned Thundurus. It has that going against it, since status is something that can really shut it down. But it can still be burned, which is bad news. While there are berries that can solve that problem, Garchomp must choose between that or a Yache berry. So he can't have all of that covered.
Those are my thoughts there. The idea is to lift the ban on some pokes and see how the DW OU metagame handles them. If it ends up being still too much to handle, by all means it can be banned again. I think that it's been a while since we've seen Garchomp, and with the shifting of the metagame since then, it's worth a try.
