It was stated numerous times in season three that Pan was stronger than even Rumpelstiltskin and that he wouldn't survive if he fought Pan, but this was never shown to any degree. Everything Pan ever did, Rumpel could've easily done, I didn't see Pan do a single thing that Rumpelstiltskin couldn't have done. The writers built Pan up to be this boyish, demonic thing that could theoretically achieve any feat he could imagine with the power of his mind, but then ultimately he's defeated by Rumpel just opening the box and him getting sucked in. I really wanted a fight between them, and writers built up to that fight, in the end to just have him sucked into a box. What are your thoughts on this?
Honestly, I have yet to see any magic weilder be as powerful as the Dark One (and that looks to be true for Emma now that she's the Dark One). I think Pan, within Neverland, was powerful, but the edge he held over Rumple was not magical, but psychological. Rumple had a lot of 'Daddy issues', and I think that may have colored some of his thinking. Also, while Rumple may have been more powerful than Pan, there may still be truth that the only way for Rumple to defeat Pan was exactly as he did.
Also, Rumple did not defeat Pan by opening the Box, as we saw. Pan pulled that last minute switcharoo with Henry, and gained the upper hand on Rumple, at least for the moment. No, the only way Rumple defeated Pan was by sacrificing himself.