In storytelling there are personal victories and then there's winning the conflict. This could be something that has both.
For some reason "Armageddon" comes to mind, with Harry reconciling with his daughter before sacrificing himself. I'm ABSOLUTELY SURE that there better examples out there though.
Yeah, but Harry killing himself was the end of the movie, the end of the story. And he won by sacrificing himself. The Doctor regenerating because he "lost" I think would be a down ending for the Doctor, and I can't see an actor wanting to leave in that way.
The Doctor sacrificing himself for a win... like in Logolopolis, Planet of the Spiders, Caves of Androzani, yeah... that works.