I think finishing the bosses will be the end of the game for those who just want to do that.

I doubt they will remove you from the world you built up, that would seem like it would upset builders and such.

But yeah there will probably be some song and dance at the end <or scrolling text saying thanks from Odin or whatever>

The game seems like it has a solid vision for where it is going so far, so I would expect some kind of end of some kind. But I doubt that will keep you from continuing if you want.