Sometimes you see a character and think wow they could be awesome under the right creator. They have the look and the powers, but every time they have been used in a story it just is not good. I'll start with someone I think has a lot of potential if they can ever get a good writer to take a shot at them.
Monarch. I know, I know the character is a trainwreck and has been almost from the start. He does have some good things going for him though. His design is just fantastic. His armor was the one thing they didn't mess up when they were coming up with the character. He is also extremely powerful which is not a bad thing at all. I even like the idea of him being a fallen hero (just not Captain Atom or Hawk) and it could make for a good mystery about who is in the armor if done right. They can even drop the "he is from the future" thing and just have a hero taking up the title in the present day.