OK, after stepping back a little, I feel like I can give a more mature analysis of this:
To be honest, the only Megalution I feel is completely unnessesary in Blaziken's, and possibly Lucario's. Blaziken is, besides being a 3rd-stage Pokemon, already strong enough as it is. I do admit I would like the design better if it didn't have those fire ribbons on its wrists. MegaLucario's design is the worst of the bunch, if only due to the giant tail and head ribbons. I appreciate what they did with Ampharos, but the design looks really lazy compared to the rest. MegaAbsol and MegaMawile I'm okay with, and I definitely appreciate what they did with Mawile. MegaMewtwo is still okay.
As a whole, I accept the Mega Evolutions much more since they're more like formes (at least from what we're getting) and we can opt out of them. I admit it still came as a damn big shock when I first read about it.
Oh, and for the new Pokes, Gogoat's prevo is cute, the others are meh.