5. Dr. Light
As soon as vicious emasculating astrophysibitch Dr. Kimoyo Hoshi makes her grand entrance brandishing a sharp-edged clipboard of doom, you know she's got the makings of a great villain:
"Silence, you miserable toad."
Way to keep those boot-licking post-docs in line, Kim! Best thing is, she doesn't even waste an exclamation point on the verbal squashing, and this is in COIE, where people say, "Pass the salt -- now, before it's ... too late!" Clearly, lines like "silence, you miserable toad" fall off her teeth-baring lips as easily as "hey, guys" does off ours.
After getting light-based powers, she'd have been perfect as the new archenemy of the Golden Age Starman; she's even got the right nom de guerre. But no. She's just another living plot point for Wolfman, a mechanism for showing that Supergirl's death is inspiring.
Didn't stick, of course. She remained a bitter, reluctant hero, burdened by her powers and a perfect candidate for a Character Donation to Marvel. As a result, no one really liked her and, if you ask me, the JLA mindwiped the wrong Dr. Light. When the real Dr. Light finally showed up to close her like his Christmas Savings Account of power, readers were more relieved than outraged.
But the new outfit, her own version of the classic black & white Dr. Light uniform? So stylish, so elegant; slimming, too. Lose the silly Scarlet Witch tiara and she'd be a stunner walking the red carpet to the Eisners, holding on to Sunburst's arm.