I have a few things to point out.
First of all, you have 5 Special attackers and only 1 physical one. If I were you, I'd switch Mega Alakazam for something like Kangaskhan, Blaziken, Mawile, etc, since Alakazam isn't really that great.
Some other things to note:
Your Rotom has 252 HP EVs and is running Pain Split. Wouldn't you rather have Pain Split fill up more of the HP bar? (Suggested spread: 252 Def / 4 SpA / 252 SpD)
Consider switching Salamence for Weakness Policy Dragonite. It gets better bulk, and you definitely should breed an Adamant/Jolly nature anyway.
I personally think that Life Orb Greninja works better, and why have Scald when you can have Surf? If you want the burn chance, you're counting on Greninja to (1) not OHKO the opponent and (2) be able to face a physical attacker. Your choice on how you want to use it, though.
Klefki didn't make it to OU for a reason. If I were you, I'd ditch it and go with Clefable.
> Clefable @ Toxic Orb/Leftovers
Ability: Magic Guard/Unaware
EVs: 252 HP / 156 Def / 100 SpD
~ Cosmic Power
~ Stored Power/Toxic
This set has worked out quite nicely for me.
And that's pretty much all I have to say.
Hope I helped!