Yeah, and come to think of it, other than setting the Battle Frontier in Kanto for some reason, they really didn't even focus that much on FR/LG, either.
And Brendan probably would have to get a larger role than a cameo if he appears in lieu of May. I wonder where May will do contests, though? She's done Hoenn, Kanto, and presumably Johto by that point, so that only leaves Sinnoh, since Unova doesn't have contests, and I'm doubtful Kalos has contests either.
As far as Mega Evolutions, I'm suspecting Groudon and Kyogre are going to be fought in Primal forms in the games, so legendaries may be the exception to that rule. Speaking of which, I wonder if the OS Mewtwo (the one from Movie 1 and Mewtwo Returns) will appear in the upcoming movie, since the next movie does focus on Mega Evolutions, and Mega X form still has to debut, it would fit that Mewtwo since it has a masculine nature.