No, MLP shouldn't got super mainstream, because it'll become all trendy and crap like nightmare before christmas. I hate the fact that a movie i grew up watching as a little kid is now some stupid fashion trend that mall kids eat up like candy.
btw, being a brony isn't mainstream bcuz if it was, bronies wouldn't be trolled all the time. Now, i agree that it would be done to death and all. infact, alot of the original fanbase would fall to pieces because of it going mainstream, just like Nightmare Before Christmas.
Besides, I like the fact that bronies aren't mainstream. because if they were, i wouldn't be a brony. being a brony is my outcry against gender stereotype. in other words, i can prove that you're still a masculine guy that drinks beer, eats red meat, and plays tackle football with peeps. now, if it was mainstream... then everyone would be a brony.