I hope this Z form thing, if real, replaces mega stones, so this way they can revive the good and balanced megas like Mega Sceptile and Mega Aerodactyl while removing the busted ones. (Mega Mence, Mega Lucario, Mega Kangaskhan...)
But if that were the case, there wouldn't be Mega Evolutions without Mega Stones. You'd just be buffing regular Sceptile, Aerodactyl, Kang etc.
I agree with Project_Mars on this one. Compare Mega Evolution, a well-received mechanic introduced in XY, to Synchro/Z-Form/whatever, something that's only happened
once in the
anime with Ash and his Greninja. Game Freak would have to do something drastically different gameplay-wise if they were to implement this over Mega forms...which I can't see happening. Maybe I'm narrow-minded, but what else could you enhance existing Pokemon with that isn't increased stats/new abilities/new typings + cool new designs? I'm treating Z-Moves separately by the way, since those aren't evolutionary/form changes. To add, Megas are quite simply all over the place, not just in the main franchise (in the anime, SSB, Pokken, Mystery Dungeon, TCG, irl in the form of toys etc). Why scrap something that has been such a huge commercial success, something Game Freak has invested so heavily in? Nevertheless, none of us knows for sure what will happen, but I will be shocked (and sad) if I discover that Altaria has been doomed to stay as a less fluffy, mediocre, non-Fairy cloud.
Also, do a Google search for 'synchro evolution'. Virtually every first-page result is merely Synchro speculation for SM. I'm aware that most of this content existed before the Z-Ring/Z-Crystals were confirmed, but it irks me nonetheless D: 'Anti-Synchro' is probably what I sound like, I admit, but I'm just attempting to look at things from a logical standpoint.