Well it is rather unusual for a young son to kiss his dad even on the forehead (ie not something that would readily occur to the writers as a possible solution for the Dark One Curse). There is also the possibility that Rumbel made the deal with his son believing that there was no other way to break the dark one curse in existence. As a result, the magic would have to be stripped from him, which didn’t possible without killing him.
In addition, maybe he didn’t truly love his son in an unselfish way. It might have been more of a possessive form of love ala Regina’s love for Henry. With Belle, it came about naturally and existed without thought. So if Rumbel falls back into his old possessive and selfish form of love, it might prevent a Belle kiss from working.
I don’t think this will be the case, though, because we can see that Rumbel has grown as a character sense he lost Belle. He was perfectly willing to give up his powers for Bae, which I think means that he wouldn’t have gone through with bringing magic to SB even if it resulted in everyone being unable to return to FTL. I wonder if the bringing of magic will return the evil of the dark one to Rumpel resulting in a regression of sorts.
Well, in any case, the final scene seems to tell us one thing: Rumpel is still a coward since the primary reason he gives for bringing Magic into the world is give himself power. Doesn’t matter that there are other and better reasons for bringing magic: protecting himself and Belle, finding Bae, maybe opening up the possibility of returning the characters back to FTL, taking down Regina (admittedly, this one wasn’t necessary before the addition of magic). I think we are going to see a three faction war here with Belle trying to keep Rumbel working with rather than against Team Snow.
Just a side note: Isn’t this so Middle Ages, all of FTL is torn apart with dashed Happy Endings all because of fighting within the “Royal” family. Seriously the main fighting characters in this (James and Snow’s family’s) are technically related in a family tree more akin to a Soap Opera. 😆 Ah but we love it so.
PS @Darcyfarrow Oh boy, what is if the BF loosely planned this whole thing. 😆 I doubt it, but she does seem to be the manipulative type. And let’s face it, SW and PC wouldn’t have succeeded in getting together without Rumpel. Then again, the SW story would be drastically different from the very beginning without Rumpel. Dang, I think I just blew my own mind with that thought.