The only thing I can think of that would result in an actual "end" to the game (i.e. no further play after the climix) would be if Alduin actually does "eat the world." That would be a very bold, very controversial, very brave choice on Bethesda's part in my opinion. It would anger a lot of people. From a gameplay point of view, I'd be disappointed as well after trying so hard to save the world. But from a lore point of view, it would be extremely compelling and open all sorts of possibilities. I think I could actually make peace with such an ending, provided there was an expansion continuing the game in the new, slightly different world or what not.
I sincerely doubt that’s going to happen, though. As such, I suspect we’ll be able to play after the ending as in every other TES game. A tease like Red Dead Redemption’s would be interesting, though. All through the first “ending,” I thought, "Damn, it’s over! Well, what a ride!" When the camera panned around
and I realized it was going to let me keep playing, I was like, “Yes!”