List of reasons this would suck ass:
1-Because of Disney's endless pandering to retarded little girls, we go back to G1 quality (Or G3 if we were unlucky)
2-The merchandise would get worse. Ok, so assuming that they buy Hasbro in this second, they would cancel Guardians Of Harmony, sue We Love Fine, cancel most of the shit that Bronies would enjoy (You know, the things that aren't pieces of plastic with a wig glued on) and stop making Official Pony shirts in a size for adults
3-It would kill the fandom. Why? They are REALLY bitchy with copyright and would shut down any fan project, including: Music, Art, Games and even Cons