Bring back the great duo of Nova Prime and Worldmind
Also, the Micronauts
Sharon Carter could be a contender with her own solo adventures but she hasn't had the shot in 50 years.
Ian Zola Rogers has spent the past few years stuck in an elevator with an AU version of his sister. His presumed dead, which is fine, but it gets weird when neither of his adopted parents even mention his existence, even would it make sense that he probably would.
And speaking of his adoptive parents...
I'm not entirely surprised that she hasn't gotten anything, but she has the background to be able to have a really awesome espionage-styled miniseries at the absolute minimum.
THE NEW X-MEN UNDER YOST
THE AVENGERS ARENA KIDS
Sersi from the avengers
So many good young characters dead or limboed
Also, tempting to throw carol danvers in here.
I LOVED the Armageddon Man story and have long waited for someone to touch on that again. I'm assuming he's still asleep, deep in some remote S.H.I.E.L.D installation (Avengers Mansion has been destroyed a couple of times).
They can’t touch Miracleman until Gaiman finishes his story and frankly I’m surprised you want them to. You really think he’ll be better used as part of the MU’s meaningless event cycle rather than separate in his own universe where he actually is important and interesting? What would they even do with him, have him job to Carol or Hulk or Sentry or whoever?
The Avengers Academy kids, particularly Reptil, Stryker and Finesse. I thought those three, in particular, had potential, in unanswered stories as to their potential and their powers origins.
Ultragirl, Suzanne Sherman (Tsu-Zana) the original human/krewe hybrid. Super strength, flight, healing factor, multi-sprectrum vision, west coast...she could be a great fun character but outside of a few story beats in the old Avengers Initiative series, shes not appeared at all. I had hoped she would turn up in Captain Marvel or the upcoming New Warriors series, but alas...no Susie.