What Marvel character(s) do you think is(are) underrated or need to be used more often?
Underrated in what sense though? DD's always done pretty great with his comics (Miller, Brubaker, Bendis, Waid) and generally accepted to be one of Marvel's more popular street-levelers, with a solid fanbase. Unless you mean underrated in the sense of a fighter, because I'd kinda agree there.
Even though DD has great comics, I still don't see that many people respect him as much as other big name heroes in the Marvel U, and like you said, he is an underrated fighter.
What he needs is a new movie to wash away the memory of Affleck :P
I think a feature film would do wonders for the character though, he'd definitely be thrown into the limelight. Look what a movie did for Iron Man. Before RDJ and the MCU, he was relatively B-list compared to Hulk, Spider-Man, and the X-Men.
S.H.I.E.L.D.? For such a massive, expensive and dangerous organization that it's supposed to be, it seems most of its time is spent with in-fighting, providing cannon-fodder, falling out of the skies and doing something wrong so they need to call in the capes.
These would just be solo titles I would like to see.
I have read Captain America and Dare Devil monthly and the Fantastic Four in trade for years, I read Hawkeye currently also. It seems I can never find solo titles for characters that really interest me from Marvel or they dont last.