>>45414792Because unlike past generations, Blaziken has Terminal 4MSS
Gen 5 Blaziken was possibly 4MSS'd because you really want Protect and SD but Permanent Sun would make Flare Blitz nuclear that it bypasses the need for coverage
Gen 6 Blaziken just cleans games the minute everything is low and even with Mega Evolutions around, old mega mechanics with speed gave Blaze the upper hand in some cases and they were all offensive but frail mons so good luck dealing with Mrs. Offense Killer. Plus if it wasn't sweeping it was wallbreaking and leaving stall open to get shredded by Blaziken's mega teammates, or Blaziken comes back when the last blaziken check dies and cleans the game. Then again it's hard to judge Blaziken in gen 5 because as far as i remember, it started the generation in Ubers and not OU (and if it did, it was probably banned the very next day)
Gen 7 gave Blaziken Z-Moves which replicated the same shit as gen 5, you're firing stupidly strong attacks that you don't need coverage to rip stall apart.
Gen 8 however took out the main thing that kept Blaziken banned (which is the ability to ignore coverage because you were firing stupidly strong attacks), making that 4MSS become a glaring issue that holds Blaziken back.
Then again, Blaziken was re-introduced with a bunch of extremely broken shit, some which hasn't been banned yet (why is Zygarde and Kyurem-Black still around for fuck's sake?) so it's just a matter of time until people remember that despite the 4MSS, Blaziken auto-wins if it sets up and has the right coverage.