Just a question: If one of the factors behind choosing Pokémon eligible for Megas is popularity, how come Druddigon supposedly has one even though from what I've seen it's one of the least popular Dragon-types, or is there another reason? I'm not saying I hate Druddigon but I'm just curious.
Presumably was done for game balance, since it was pretty mediocre. Popularity is obviously the primary factor, but they do consider the other two occasionally.
In any case, I'm really surprised that more Mega Stones haven't been discovered. I hope that a ton of them turn up in the postgame, or that the leakers just weren't doing much exploring. I suppose there's also the chance that the Pokemilage Club could offer some, too, or maybe even that wild Pokemon could be holding them at a low rate.