I don't wanna be
too abrasive, but, if you really believe this then you are literally ********. Even
if Mike Z would, for whatever reason, give up his engine to the MLP:FiM team (which, by the way, you haven't exactly delivered any proof of, nor can I find any news on it), there's no way the MLP:FiM would give up literally
a year and a half of progress in their own engine, especially not when the game is so close to being finished. The last demo we saw of the game had five characters out of an initial six being playable. This was around September 2012.
There's no way the developers (or, for that matter,
any developer) would completely restart their project to rework it in a different engine after more than 18 months to development. It's just not happening, and you're honestly kidding yourself if you really believe this.
Also, Mane6 has expressed a multitude of times that even though their engine is unruly to work with, they've done a lot of work to improve on it and they feel like "wizards" with it now. They're completely comfortable with their choice of engine, so it'd seem asinine to simply trade it in for a "better" engine.
I'd also like to say again that Mane6 gave shout-outs to both Melee and Skullgirls on their site, saying "vote for these two instead, vote for what you really wanna see at EVO". I've done my own research and found absolutely zero evidence of MLP fans suddenly voting for Skullgirls because they were asked to. If you think "bronies are the main threat to Melee", you're honestly being delusional as there's absolutely no evidence whatsoever to prove this theory right.
Rather, the main threat to Melee is the fact that, apparently, fighting game fans would rather donate to Skullgirls. I certainly don't think it's the right choice, and you'd think after Apex the FGC would be more open to Melee being featured at EVO again, but apparently not. So it's up to this community to put their heads up and make **** happen, rather than blaming others without evidence.