CLOWN.
OK, we all know these guys are on the outs with the gods (may their beneficence be eternal) who run the Champions Universe. I can see why -- too goofy. However, I think we can see lots of viable non-goofy characters based on comedy themes in the comics that have worked well -- Joker, Riddler and Arcade come to mind, and I'm sure there are many others.
Do you see any way to reincorporate CLOWN into the mood of the current CU, by tweaking them, toning down their silly factor and so forth? If DC did it to the Silver-Age Joker, I don't see why we can't do it to CLOWN.