Unfortunately, that's not a very strong statement since that only happened a year and a half ago, but still, here's another one we can add to the category of really bad calls.
The combination of Swagger, Foul Play and Prankster, better known as Swagplay, had been under scrutiny for a while, and after discussion on the subject degenerated very, very badly, the decision was taken to give it a proper suspect test. Unfortunately, the voting ended up being on Swagger alone, instead of being in combination with Foul Play or Prankster. And words can't express the shock I had when I found out about it. I mean, sure, Swagger is a really bad move overall, except when used in combination with Foul Play, which gets its damage doubled by Swagger. So the competitive impact of a Swagger ban beyond Swagplay being forbidden would be practically non-existent, which is a step up from Sand Veil which could've had legitimate uses on other Pokémon besides Garchomp.
Still, it's the principle of the thing. Swagger alone isn't at all problematic, since as I just said it's a terrible move, and neither is Foul Play alone, which is a tremendous help to Pranksters and other support Pokémon like Mandibuzz. It's the combination of both that's debatably problematic, and as such I strongly believe a Swagger + Foul Play combo ban was the way to go. Yes, I'm not a huge fan of combo bans as a whole, but with an increasingly complex and synergy-based game, where rating moves and abilities on their own becomes borderline unfair, it's a necessary evil we have to put up with.
Obviously, this doesn't suddenly mean I believe the likes of Blaze Blaziken should be allowed in OU by just combo-banning Speed Boost and Blaziken. Nerfing various Pokémon just so they could be allowed in any tier would mean it would happen for just about everything in every tier, and of course we can't have that. On the other hand, doing it for combinations of moves, items and abilities is fine, since there's no real danger of a slippery slope effect there, as proven by the years following the Swift Swim embargo. For example, I'll point you towards the Endless Battle Clause that was put into effect a few months ago. It bans the combination of a Leppa Berry with either Harvest or Recycle, and even though Leppa Berry is completely useless beyond that, they still went ahead and did a combo ban anyway, because all the components of the ban are completely harmless on their own. So why didn't they do the same here?
Also surprising was the enormous blowout in favor of the ban of Swagger alone - 66 to 11. Not only because I would've imagined more people didn't like the idea of NOT doing a combo ban, but also because Klefki, the primary Swagplay user, is one of those Pokémon that fell out of OU with the tiering changes that only see the top 2% have a significant impact in the usage stats, suggesting Swagplay was more of an issue at lower levels of play, while better players could get around it better.
In the end, while banning Swagger alone doesn't have any effect beyond just getting rid of Swagplay, which was the intended goal all along, I still have a major problem with that way of doing things. What if someone wants to use Swagger for, say, phazing? Sure, it's far from the best way of doing it to say the least, but it's a universal move, and I guess it could work decently in certain contexts (such as opponents with no physical attacks). So I despise the notion of taking that option away, even if it's hardly a stellar one.
So, are you happy now? I did say I'd complain if something like that happened, so here you go.
Edit: Because I may not have been clear enough, let me reiterate: I see fundamentally nothing wrong with doing something about Swagplay, though I'm not nearly skilled enough to know for sure whether it's the right thing to do. However, preventing use of Swagger for what it was originally meant to do, even if it's bad at doing so... let's just say I'm not a fan. That's why I was hoping it'd be a combo ban with Foul Play.