It looks like there will definitely be some sort of DLC coming to Mega Man 11. The question is... what is it? Playable Protoman, Bass, or just the soundtrack included with some special pre-orders. Let's hope for the unlock-able characters. The possibilities are endless when they're in-app... so lets hope it's not like that iOS version of the game where you can unlock power ups for money.
Here are screenshots from the XBox Online store showing the in app purchase feature.