Well, we know that magic in Storybrooke is different. He seems to have no trouble, but there may come a time when he does run into some complications with his powers. Perhaps Captain Hook finds a way against his magic–maybe Cora taught a bit to help him gain an advantage against Rumpelstiltskin.
It could be that Rumpelstiltskin’s favor would be for Emma to fight him–she already tricked him once, and she is a strong fighter. 🙂