In addition to what Seal the Deal said (ESPECIALLY ABOUT QUICK CLAW), I don't usually recommend having two of any pokemon of the same type on a team., unless it's something like Sap Sipper or Water Absorb. So replace Gallade with a mon with these types: Grass, Ice, Flying, Poison, Fairy, Psychic, Ghost, Rock, or Electric that doesn't already share multiple weaknesses with your team. I would probably use a contrary Serperior because it's broken but that's just me.
Also, you have one special attacker. I think that's very bad if your Greninja is KOed and the opponent sends out something like an Avalugg that is extremely physically bulky.
I would replace Scizor's Toxic with U-Turn and Flash Cannon with Bullet Punch.
Please never run any special attacks on Snorlax. You can replace Tbolt with Crunch for some good coverage. On top of that, Giga Impact is really bad compared to Return or even Body Slam. Heck, Curse is a good move too.
I completely agree with what Seal said about Flygon's set.
Greninja has a decent set but I think it needs Extrasensory. Maybe that over Water Shuriken (I mean, you don't have Battle Bond).
I don't like Sky Uppercut on Blaziken because it's inaccurate. Superpower or even High Jump Kick would be better. Replace Blaze Kick with possibly Swords Dance or Bulk Up because you already have a fire STAB.
Next I want to talk about EVs. I'm not sure if you have your mons EV trained but if you haven't definitely do it. It will make fights a lot easier.
For items I think Greninja should have Expert Belt, Scizor could have maybe Choice Band (if you replace Swords Dance with Knock Off) or just give it the Scizorite or Leftovers, Blaziken could take Life Orb, Flygon holds Groundium Z, and then do something with that sixth member. I would make it bulky and maybe give it Assault Vest.