sounds like pretty much every other Bethesda main questline.
Morrowind: you kill Dagoth Ur, Azura stops by and says hello, and you're free to go do whatever.
Oblivion: Martin banishes Dagon, Ocato stops by and says hello, and you're free to go do whatever.
Fallout 3: you turn on Project Purity and die. (OOPS.)
Skyrim: you kill Alduin, Tsun stops by and says hello, Paarthurnax stops by and says hello, Odahviing stops by and says hello, and you're free to go do whatever.
what were you expecting? the game to end?