Who doesn't love The Big O? I mean, besides Mike Lazzo and Kim Manning of Adult Swim. No, they prefer Tim and Eric's "humor" abortions and stoner cartoons.
Did the show need a third season? I think a small OVA would suit it, or a movie, to clear up some of the unsolved mysteries and strange events that seemed to go unexplained or even all that hinted toward explanation. However, I think many of the answers you might be looking for are already in the show, if youre paying attention. I just recently watched it for the sixth or seventh time, and I finally have a good working theory as to what occured, and evidence to support it. I may just present my argument here.