I always dismissed MUGEN as being a case of too little for the amount of effort required. Half of MUGEN's appeal was hunting down and swapping rare characters, or creating your own. Both of them took work and there was no guarantee that they'd be balanced or move with any sense of fluidity.
However, if this is an all-encompassing MUGEN-like package, where all characters are the same size and move with the same framerates, I'd at least give it a try. There's still a thrill to be had by whipping Squall's ass with Simon Belmont. All MUGEN ever needed for to be interesting was some uniformity.
I'll bet that many of the characters are essentially palette swaps. What I mean is, that there will be a limited number of movesets existent within the game and each character will have their animations based around one particular moveset. In the end, it wouldn't be about deciding whether Kratos is strategically better than Ky Kiske, but whether Moveset X is consistently better against Moveset Y. All characters using Moveset X would have an advantage over all those assigned to Moveset Y. Once you know which moveset you prefer, any character using that set becomes instantly playable and all further choices would be purely cosmetic, if this makes sense to anyone.
With so many cards and sprites, this would seem to be the simplest method of designing gameplay. As long as the movesets are fundamentally balanced, the whole game could be fun.
Of course, if it leads to any amount of popularity and praise, the infringement lawsuits will be staggering.
Also:
INSTANT WIN
Jam it back in, in the dark.