The question of whether a Blu Ray drive will be included keeps bouncing around the usual circles, which I think is part of the equation when it comes to gauging just how far into the "multimedia" side Nintendo will go. Personally, with those players becoming so relatively inexpensive from a consumer standpoint, I think it's hard for a game system to create value by increasing it's overall costs for something people can buy for $100 these days as a standalone player. But will a standard DVD do the trick in terms of storage for "next gen" games? Even Microsoft (who has officially stated they won't use Blu Ray) is tinkering with new disc formats to get more space and combat piracy.
For me (primarily thinking as a collector) I'd like to see the return of game carts with Project Cafe. Flash memory has gotten cheaper to produce and carts are less prone to damage from scratches, etc. It works for DS/3DS, I don't think it's too far a stretch to think carts could make a comeback in some shape or form.
As far as the multimedia stuff goes, I think Wii's success with Netflix (more people watch Netflix on Wii than any other console) along with 3DS's prospects for Netflix as well as 3D movies kind of shakes things up a bit. But I think they'll always market themselves as a game system first.