I hardly believe any further Legends Title would be for Nintendo.
Why not? MegaMan's generally been best received on Nintendo's platforms.
How many series failed on Nintendo? ZX, arguably.
How many series failed elsewhere? X, MHX, PU, Legends.
Nintendo is oldschool and MegaMan is oldschool. I don't think it's any stretch that there'd be a correlation in the userbase, especially since at the release of MHX/PU the phrase, "I'd buy those if I had a PSP" was freaking everywhere on the internet. The sooner Capcom realizes that, the better.