Previously, our tiers have always been governed by a firm belief that setting any form of potentially consequential precedent should be avoided. The individuals at the helm of Smogon had a strong fear of running into a slippery-slope in terms of tiering policy. However, the OU council believes that this should not hold the OU tier back from evolving into the best metagame possible. Moreover, unbanning Blaziken with the ability Blaze is a strong first step in the right direction.
Before we address how Blaziken might fair in the environment of SM OU, it is worth elaborating on the fact that this decision does form a future precedent in its own, perhaps provoking future suspects, retests, quick bans, and unbannings to be conducted in a different fashion than previously done. There are now near countless, innumerable options to contemplate from a tiering perspective and, therefore, this promotes healthy, intelligent discussion from a communal perspective in order to determine the future of Smogon's tiers and shape the metagame in the best way possible. The council is optimistic about what is to come as a response to this realm of possibilities opening up and will address the situation with a high degree of passion and forethought.
In the SM OU metagame, Blaziken with the Blaze ability will be an interesting prospect. While it wields a disappointing Speed tier, it makes up for it due to outstanding offensive capabilities on both sides of the spectrum and a satisfactory pool of moves to chose from. Unfortunately, the trends of the metagame are not too friendly to Blaziken due to Toxapex being one of the most common defensive Pokemon and Tapu Fini still being a viable option, but it can work around this with moves like Swords Dance and Thunder Punch if played well. Moreover, Blaze Blaziken will be an interesting addition to the tier and, surely, much less controversial than Speed Boost Blaziken was in the prior two generations.
Finally, it is worth noting that this is not something that is too random or out of the blue. Fellow council member and prominent member of the OU community, PDC, foreshadowed the prospect of something happening in regards to Blaziken in the past here in a Policy thread dedicated to the prospect of Blaziken in the OU metagame. If the necessary people ( The Immortal ) could please implement the change on PS, it'd be appreciated