Brad, indy's can self publish on X1 as well. They just have to do it under the indy banner...which in the past was problematic as that content was hidden in the marketplace. With X1 MS fixed that so all games, be they retail or XBLA-like or indy titles are all just listed in the marketplace as 'games'.
I don't see how this is any different in practice than what Sony is doing. Make a game, pay the $99 fee to get it self-published as all indy's do, it goes up for sale at the price you choose for it. Already have an indy game finished for Windows? Take your Windows version, tweak the controls for X1, and self publish, etc. Seems smart to me. The real differentiators imho will be exposure.
Personally I'd LOVE to see a Kickstarter-like app for X1 that lets gamers donate to new indy titles or general app projects. I'd like it even more if MS did this for their indy devs and had Kickstarter as part of the marketplace itself.