I actually kinda like the Province trashing on Queen, but I think it would be more interesting on a card that does it as an advantage for you. My main problem with such uses would be the overlap with Salt-the-earth. Anyhow, I think Salt-The-Earth shows that a combination of trashing VP cards and getting VP tokens clearly makes sense. Queen just shouldn't be able to go nuts as much with that. If it was something like "At the start of each of your turns for the rest of the game, you may trash a Province from the supply, and if you do, +3VP", maybe it would be easier to balance?