I will be voting to ban Blaziken. Here, I will talk about both the sweeping Blaziken set (Flare Blitz/Hi Jump Kick/Swords Dance/Protect) and the Baton Pass set (Swords Dance/Baton Pass/Substitute or Protect/Hi Jump Kick or Flare Blitz). I’ll probably talk more about the sweeper set, as I have much more experience with it.
First, let’s look at the sweeper set. There are very, very few answers to this set, especially when combined with sun support. The most commonly cited checks to Blaziken are: Breloom (revenge), Gyarados, Dragonite, Salamence, Jellicent, Slowbro, Gliscor, and Tentacruel. Breloom and Dragonite need Blaziken to be around 50% for them to revenge with Mach Punch/Extremespeed, otherwise Blaziken kills both of them with Sun +2 Flare Blitz (after sr for Dragonite). Gyarados and Salamence are both outsped and ko’d by Hi Jump Kick after Stealth Rock (Blaziken can protect and get two boosts versus scarfmence). Jellicent is 2hko’d by a +2 Flare Blitz in the Sun (68% chance to be ko’d with Life Orb), while it only does 40% maximum with Scald, while Tentacruel suffers the same fate. If Blaziken holds Air Balloon, Gliscor can be used to obtain another Swords Dance boost. Regardless, Gliscor is ko’d by a +2 Flare Blitz in the sun anyway. The only true counter to Blaziken is Slowbro, who is pretty much forced to carry Psychic (or Thunder Wave, which kind of cripples it), otherwise it’s in the same boat as Tentacruel/Jellicent.
What about not letting it set up, then? The problem with this is that, especially if Blaziken holds Air Balloon (the best item!), there are quite a few areas for him to set up. Chandelure locked into Energy Ball/Hidden Power Ice, Mamoswine, Gliscor, and Ferrothorn lacking Thunder Wave are only just a couple of examples. This isn’t including all the pokemon that it can scare out; after a Protect, many pokemon are forced out thanks to Blaziken’s sheer force and speed. Sure, you can predict and try to cripple Blaziken by Thunder Waving it with pokemon such as Ferrothorn and Blissey, but you risk having it attack and kill an important member of your team instead of Swords Dancing. Usually the only thing stopping pure sweeper Blaziken is it killing itself through recoil, or getting outpredicted against something like tar + chandelure.
Baton Pass is a completely different monster. Blaziken by itself is an amazing sweeper in its own right, but the ability to pass +2/+2 rather easily to other sweepers is absolutely scary. Bulky waters stopping your sweep? No problem, just pass your boosts to Dragonite, Garchomp, or even Serperior; who still enjoys the +2 Speed. What separates Blaziken from something like Ninjask is the fact that Blaziken, even with Baton Pass taking up a moveslot, makes for a respectable sweeper in its own right. It still hits incredibly hard with a +2 Flare Blitz, or +2 Hi Jump Kick while retaining the ability to escape counters and turn a different pokemon into a complete monster.
To conclude, sweeper Blaziken hits like a truck and has almost no counters with the correct support, while Baton Pass allows you to sweep with other, equally dangerous pokemon in the face of a Blaziken counter. Both sets also do not have too great of difficulty in setting up. Ban Blaziken.