I would actually love to have seen him become something entirely new, a light energy Dixingren, but that's my id.

Oh hey, that would be cool, I like that one!

And it really would've fit better with the show's themes, to me (one of my biggest problems with the ending, aside from the character death, is that after a whole show's worth of examples of how Haixingren and Dixingren can learn to get along and work together and love each other -- in the end the worlds are completely separated. To me it's a tragedy presented as a victory, and was unnecessary besides...)