For some of the biggest things:
Salamencite -> Ubers (I honestly don't even think that this should be put to a vote in this thread, as it's so blatantly broken that it shouldn't even really need any discussion)
Mawilite -> Ubers
Greninja -> Ubers
M-Mawile is ridiculous. The only way to beat it is with fairly obscure stuff (Weezing, Chandelure, etc.)
Greninja, with the coming of ORAS, got a couple of new toys in the form of Gunk Shot and Low Kick. Now, things that used to be able to wall Greninja get killed rather easily. It only needs 40 attack to OHKO max HP Azumarill with Gunk Shot, for example. Sylveon gets OHKOd by Gunk Shot
M-Salamence lol
Also some other things for the new mega stones in no particular order:
Glalitite -> Inspired
Audinite -> Stay in Tesla because garbage
Galladite -> Standard
Lopunnite -> Standard
Beedrillite -> Creative or Standard (not sure which)
Pidgeotite -> Creative
Slowbronite -> Standard
Steelixite -> Inspired
Sablenite -> Standard
Sceptilite -> Creative
Swampertite -> Creative
Diancite -> Standard
Metagrossite -> Standard (I'd kinda prefer ubers but I don't see other people really agreeing, so we'll get there when we get there)
Altarianite -> Standard
Sharpedonite -> Creative
Latiosite/Latiasite aren't really that great so they should just stay where they are.
Also, as Diancie is currently untiered, I'd personally say it should be in Creative.
