Pretty Face was funny but I don't think the mangaka intended any deep analysis, there are far too many plot holes, some of which have already been mentioned. For funny sex change manga though I prefer Gachagacha (by Hiroyuki Tamakoshi), though I can't explain why exactly.
As for the loose ends, the mangaka himself says that he didn't want to resolve them since it would be admitting that the series was over, and he couldn't bring himself to do that. (If people haven't seen the mangaka's parting comments in chapter 52 I can post the scan from the Akatsuki scanlation)
I was interested to see the alternative ending that was considered (that Randou was in a coma ever since the accident in chapter 1 and it was all the dream of a dying man), which would have made the story rather like the film "Jacob's Ladder" where an army veteran finds himself in a similarly surreal situation. That would have been pretty depressing though.