Why are you guys still talking about talonflame and azumarrill as if they countered blaziken? Who in their right mind uses SD when you know TF and Azu are still alive? Thanks to team preview, Azu and TF achieve one thing. Deal with bad players who SD right away and keep blaziken from wrecking your team from the get go.
When i see TF i make sure Ken doesn't go in until rocks are up. Then when it switches in TF dies. Azu on the other hand becomes set up bait for my dragons, since its forced to use a weak AJ. It already took SR damage and got hit by HJK. It no longer walls my dragons.
The only way TF and Azu counter blaziken is if the other player is bad. Anyone with a brain can destroy teams whose only two checks are mediocre polemon.
I don't want to step on anyone's toes here but we've mentioned lots of checks/viable tactics that throw a spanner in Blaziken's sweep attempts in this thread.
Also the argument that "you don't switch blaziken in until its checks are dead" doesn't hold because it applies to roughly EVERY SWEEPER EVER.
Another thing that applies to every sweeper ever is using calculations based on a +2 Blaziken OHKO / 2HKO'ing mons' after SR.
I'd challenge you to find another common OU sweeper that isn't quite frankly ripping apart the opposing team if it's sitting at +2 after setting up and you have stealth rocks up on your opponents side of the field.
There's plenty of stuff that Blaziken can't switch in on without being killed (any one who can survive an unboosted hit / is faster than base speed Blaziken and has Earthquake for example).
Arguments like these:
"you don't switch in Blaziken until its checks are dead"
"you don't use fighting coverage when your opponent has a live Ghost on their team"
"you don't Swords Dance when your opponent has a live Talonflame, Azumaril, Mega Pincir etc with OHKO priority"
These don't serve any point other than proving that Blaziken runs into the same problems as a lot of other OU sweepers.
Again, saying that Blaziken is really powerful if it has switched in on something that can't hurt it, gotten an uncontested Swords Dance and you have hazards up does not justify a ban alone since it applies to pretty much every set-up sweeper ever.
I'm in no way saying that Blaziken is not great. I think it's justifiably OU and heck, might even be better after a bunch of testing, but it's too soon to make that call, especially without community interaction.
EDIT: Also I'm seeing a lot of "Mega Blaziken too powerful compared to normal Blaziken" and thought this could do with some clearing up. Life Orb regular Blaziken actually hits marginally harder than Mega Blaziken.
The real advantage of Mega Blaziken is that you get very slightly higher bulk, a higher base speed for SB and not have Life Orb add to the heavy recoil and self-damage Blaziken already takes from Flare Blitz and HJK.
This is actually a pretty humble increase in power for a Mega Slot when you consider how game-changing Mega Pincir, Gengar and Kangaskan's forms are.