Why are we still picking on Thor?
Yes, it would have been nice to see everybody get happy ending.
But the reality, actual drunks fall off the wagon a few times. People stumble. Thor might regress again or hasn't quite lost his wanderlust. Got a few things to work out, yet. He didn't actually figure out what he wanted to do from all of that movie, that was just him dealing with the problem that he got dragged back into.
Hemsworth said he was done being Thor, but here he is with a non-retired ending. So there we are. He'd have asked for an endier ending if he wanted it.
Besides, he'll change up the dynamic of GotG. Quill won't hit on him, because he's still pining over Gamora.
What would GotG been if Quill got the G back at the end? The same team-up we had in the last 2 movies. So now, the 3rd one will be different.