I'm happy, though confused as to why, Aggron loses it's Rock typing. Maybe it refined the rocks on it's body? Though, I'd rather have the Fire weakness over 4x Fighting and Ground weakness (Plus Filter. YAY). Really love this guy.
Also, although it gains the Shadow Tag ability, MegaGengar is... not my favorite. First of all, since it takes a turn to MegaEvolve, Gengar wont be popping up and trapping anyone unless he had previously MegaEvolved. And then without Levitate, he gains Ground weakness.
I understand MegaCharizard X can go in Sky Battles, but since Gengar is practically phasing through the floor, I wonder how that will look. I mean, at least Gengar is proven to float (Also makes me wonder how Electross will work...).