I think it was Emma who mentioned about what is needed to pull Excalibur not Rumple. Now whether or not she is lieing about it is something we have to considered. All around I was surprised that Rumple was able to pull the sword out of the stone, since I assumed it was going to be Henry. It makes since he isn’t the dark one, and he has the best chance of receiving redemption now that he isn’t cursed. Besides seeing how dark Emma has become does gives an insight to how difficult it must have been to try to control the darkness.