Do we have any confirmation that ORAS will contain every single XY mega evolution? I'm sure it won't have every single XY mega stone since it's got many mega stones of its own, but I was thinking... I know that would be a weird move, but since they're creating an XY and an ORAS League, maybe they won't program some megas into ORAS so XY doesn't completely lose out. Only that would keep XY from fading into obscurity (and trainer customisation to an extent). But that would suck.
I hadn't even considered that, realising that we can't transfer items unless we can trade between XY and ORAS. I hope that we keep XY evolutions though, and it makes sense to me. This is mere speculation and pretty weak reasoning but it goes as thus: In the anime special of mega evolutions we have that guy who's name I forget with the MZard going to Hoenn to kill every Hoenn Mega. Therefore the games are similar...? Whether we'll find XY stones in ORAS or they will be transferable who knows, but we can dream right?