It would be cool if you could get a "Final Quest" from Ambrose, in which you fight all the bosses again to ensure they never err... do "bad things" again.
It would be nice if it was only the bosses that drop rare items, including Spike the Crusher, Smogger, and Yakedo.
I've mentioned this a few times but with no or little response. I think it's a great idea. I suggested that they give you something like another training point, or 5000 coins, or maybe a rare sword/wand/staff for completing this.