I agree 100% and was coming here to the forums to post the exact same thing. The commenting system in P2 is outstanding and most of the existing comment plugins are terrible. I've looked at the code too and its implementing well using the Jquery capabilities built into the WordPress Core so you can be assured of no conflicts.
P2 is awesome as a concept and as a developer myself, I totally understand why its implemented as a theme. However, the "style" of it is not for everyone. Its great that child themes are now possible. However, I really would like to see the ajax comment system and possibily even the post publisher (probably without the various post types, though as those significantly complicate adding P2 capability to other themes) implemented as plugins. This would allow any site with any theme to take advantage of these features.
Any chance of this happening guys?