For those wanting something else, remember that these things don't have to be exclusive from one another. Given Capcom's tendency to milk franchises, nothing says they can't start releasing ________ X Mega Man titles semi-regularly alongside other Mega Man titles.
Personally, I think these little 8-bit games would make excellent pre-order bonuses, or even simply be released as freebies to whet player's appetites.
It'd be fun but I'd much rather just have a new Megaman game as well as a new Darkstalkers game XD
What about one that bridges the X series with the classic series? It could be Megaman X X Megaman...looks too much like a bad porn title O.O so we reverse it...Megaman X Megaman X...too repetitive so its Megaman X²....ugh we already have that game title! Naming might be a problem for that idea :P