Characters who deserve a major push and the Wolverine/Bucky treatment?
1] The Wasp - She seems to be a hard character for writers to write but as a veteran Avenger and one of the MU foundation characters she's long since due for a much stronger and more assertive treatment.
2] Count Nefaria - Like you I see him as a very underused villain who can work as either evil-Superman or Maffia don. He's another one of those MU characters who despite having a long and distinguished history never gets any attention.
3] Doc Samson - There have been odd times he's been handed a full superhero role and been extremely impressive. A highly intelligent man he has a fascinating contrary attitude to his power and what it should be used for. He could be a very interesting major player as he has the respect of a good deal of the superhero community and a psychologist superhero is fascinating territory.
4] Hellcat - Like the Wasp a character with a distinguished history and a lot to offer. Spider-Woman and Ms Marvel got their chance at the bigtime again, Patsy Walker is a shameful exception.
5] Baron Von Strucker - Although he appears occasionally he reminds me a little of the Mandarin, both extremely dangerous but neither making much impression on the MU as a whole. With what his background is he should be a far more dangerous and global threat than what he has been presented as. I'd like to see him beefed up to be a major force in the MU supervillain stage.
I could see Hellcat moving up to becoming the MU's premier occult investigator. After the time she's spent in hell, she's gotta be teh most trustworthy of the most qualified.