I like the idea of getting a sudden power-up mid battle. It always disappointed me that pokemon could evolve during a battle in the anime but not the games... Of course since the form is temporary I wouldn't call it "evolution." It certainly supports using your starters more often along with myriad of other Pokemon!
P.S. Love your reaction. The last pic I was on was a mega "evolution" hate pic. Everyone has their own opinions, but complaining about them isn't going to get rid of them. I don't think there are enough people that hate the idea to do that.