Mega evolutions would be a great outlet for gym leaders during rematches post-game. Roxanne would get Aggron, Brawley Medicham, Wattson Manectric, and the list would go on. I would really like to see that, adds an extra challenge to one of my favorite parts of the original Hoenn games. A few more Hoenn megas would have to be released to make this a possibility, but I wouldn't say it's a crazy theory by any means.