Nothing good can come of differing health values.
Blazblue, SF, UMvC3, all good games in their own right. Unless of course you meant nothing good for MK specifically.
This is one of two reason why I say no...because we would have a character(s) like Dark Phoenix and would make the game rediculous
Why would differing health values guarantee a character like Dark Phoenix? Just because it makes it easier to make and balance a character with resurection style super doesn't mean you
have to have a character like that. Also I don't play UMvC3 but I'm pretty sure they successfully balanced her out after the mess up in vanilla, so water under the bridge.
I personally think it would be cool, characters like Kabal can be more justified to have ridiculous amounts of tools because they have less life, characters like Sheeva need a bit more on their side to compensate for slow as fuck normals.
But as said, MK has always been damage in percentages, not actual values, so they'd have to change that. So even though I think differing health does add depth to characters, I don't trust NRS with too many changes so I agree with:
Let's give NRS a chance to make a game a fully functioning game first before we ask for more variables.