How about the abominable snowman from Superman #266? The one who could turn Superman to ice just by touching him. I bet they could make him really scary looking today, even give him a better origin.
Now THAT is a cool idea.
I would like to see the return or revamp of Super-Menace.
Have you read the Subjekt 13 story?
(Written, I should add, by your old rival from the Roy Thomas INVADERS lettercols.)
It pretty much WAS a revamp of Super-Menace (though it at first did not appear to be so, an unexpected plot twist). And it was a very emotionally powerful story.