There's something I just thought of in regards to the 3DS division. IDK if you all know this, but
earlier this month Nintendo said that there will not be a patch for X/Y for the Mega Evolutions, Pikachu forms, and Primals that ORAS is introducing.
If I'm understanding
this page right, X/Y and ORAS can't do random Battle Spot battles with each other, but they MIGHT still be able to battle each other via the PSS like we've normally been doing with the 3DS division.
But even if that's the case, there's still the issue of new Megas. No matter what, you can't battle an X/Y player if you're using a Pokemon holding an ORAS mega stone. We can't really expect all the challengers AND all the leaders/E4 members to have X/Y and/or ORAS. Some people are only gonna have X/Y, some people are only gonna have ORAS.
So what are we gonna do about the compatibility issues in regards to ORAS mega stones?