I like the idea of having to go back and do in a bunch of lower level critters in order to advance. (Why didn't I think of that?) So there's another +1.
On another note, I don't think I've ever seen a guild with an eagle eye or exterminator medal. Not that I don't think they exist, just that they're definitely the hardest ones to get. Any idea who has one? I like to stare at it and envy them (we're at 1% and 5.3% respectively)