Mr. Byrne's FF without powers would seem to me to be, effectively, the Challengers of the Unknown (ref. Amalgam's "Challengers of the Fantastic.") That's not a complaint; I would LOVE to see Mr. Byrne's take on the Death Cheaters!

It seemed to me that IDW's "Byrne Super-verse", with Trio and Helix, had many more stories to tell, and I would have loved to see those.

I'd've loved to see more of Danger Unlimited. Maybe they were set in that prior BS-v... there were several super heroes in DU (including the Torch of Liberty, whom I would enjoy seeing more of as well!)

In general, most of the Byrne books that got cut off - Captain America, X-Men (although Elsewhen whets the appetite!), Fantastic Four, the Hulk, etc.

I really wanted to see the OTHER ending to Crisis on Infinite Earths. I talked to a couple of DC pros who said that if sales and response weren't good on COIE, there was a storyline to revert everything back to "status quo."

Mr. Byrne has noted that he had a storyline to go from "Whatever Happened to the Man of Tomorrow" to "Man of Steel" organically; not simply a dead stop and restart; but a story that reverted everything naturally. It sounded great!

1.  The X-Men/Legion of Superheroes crossover by Claremont and Cockrum, circa 1982.  When DC's New Teen Titans book took off and unexpectedly became DC's best seller the Titans were swapped out for the Legion, and Dave dropped out of the project.  Seeing Dave draw the two teams he made famous would have been amazing. 

2.  Howard the Duck revival series circa 1986.  After Gerber settled his lawsuit with Marvel he was slated to return with an all-new Howard the Duck series.  He wrote the script for the first issue (a parody of Secret Wars, Crisis, and "event" stories in general) but Shooter asked for changes that Gerber wasn't willing to make, so he took his script and walked away.

OMEGA THE UNKNOWN--I think Steve Gerber's basic plot was genius, but it might have worked better if it had shown up in the 60's or 80's, and then it sadly ended on a cliffhanger that was ultimately finished up by somebody else.  (Of course, I would take another 100 Gerber issues on anything he ever worked on.)

SPIDER-WOMAN--I've mentioned this before, but Mark Gruenwald's relatively short run of this Los Angeles-set series is one of this LA native's all-time favorites!  He and Carmine Infantino somehow got the weird feel of my home town just right.  I guess at Shooter's order, Mike Fleisher and then Chris Claremont wrote 180 degree takes that weren't even the same character.  Gruenwald was heartbroken as he had plans for 100 more issues (some of which, I assume, he used on his 120+ issue run on CAPTAIN AMERICA).

STAR-LORD
BLOODSTONE

--the writers of these (Steve Englehart and John Warner) had great plans for these characters--epic plans--that were totally truncated.  (It's interesting that the GUARDIANS OF THE GALAXY VOL. 2 movie sort of completed Englehart's original "godlike" idea for Peter Quill.)

SUPERBOY & THE LEGION OF SUPER-HEROES--Jim Starlin's follow-up to his brilliant issue #239 (possibly my all-time favorite single comic issue) was supposed to be a big special with twice the pages but was instead whittled down by the new editor to two regular issues, inked by the totally inappropriate Dave Hunt, prompting Starlin to call himself "Steve Apollo" and never go near the Legion again.  In hindsight, 239 and the sequel would be the type of thing to forever be reprinted in all formats (including oversized hardcover "ultimate" or "artists" editions) and possibly spawn a billion-dollar movie.  But, hey, editors have to show artists who's boss every so often, right?

Yup!  Great stuff!

Love it or loathe it, Peter David being allowed to wrap his Hulk run up with issue 500.