Prince of Thieves is only useful when enemy resources > you, and now it has a max of 20 cap, so I don't think it's that horrible, although it is an annoying card when used against you. If you manage your deck well and can keep your resources low that card won't be as useful against you. Even if you try to go for Resources win or Big card win, you can discard the prince with 8 resources each (forgot the card name, it's uncommon), take a chance with Tribute, Black market works too