I'm thinking there should be some minor skirmishes before a true final confrontation. Like maybe send a few warriors through a mirror to intercept Rumplestiltskin and basically do a test run to see how powerful he is against a squadron of similarly empowered heroes, not necessarily trying to defeat him then and there, but to assess his power and see how much more they would need to be able to win if it came to a true life-or-death final battle.<br/><br/>This could also serve for the seeds of doubt in Koschei's mind that allow him to try to defect to Snow White's side, having encountered her and her friends in person.