We tore out all the tile and stripped the walls behind the tile down to their studs. We removed the tile on the floor, repaired the rotten floorboards, fixed the plumbing, and removed the bathtub and the vanity.
Oh, and did I mention the entire process took a year and a half? (Since we had another full bath to use throughout, we took our sweet time.)
Still, I'd say the results were worth it.