Reporting for duty!
(has super-flu and has limited window between codeine laced cough syrup doses that he's cognitive...yesterday, hugged mailman and thanked him for his commitment to socialism)
Ellis is definitely Mount Rushmore of British Invasion writers! (Moore,Gaiman,Morrison and Ellis...I love Ennis but he's in the Crazy Horse Memorial slot. Fight me nerds!)
I can agree with @darthmongoose that he's lesser known than the other three but not because the bulk/quality of work. He just never really "weaponized" his persona enough in the U.S. market enough to make that next leap in fame.
He has been a consistent star maker for his artist collaborators, something the other Brits don't do as much IMO. Hitch soaked up all the THE AUTHORITY love and rolled into THE ULTIMATES. Cassady did the same with PLANETARY. Declan Shalvey got the rub off that excellent MOON KNIGHT re-imagining.
I think barring any new upcoming exciting works, he needs someone in Hollywood to make TRANSMETROPOLITAN their passion project and cast the fuck out of Spider Jerusalem (I lean James McAvoy but there's a dozen great choices). Then ride that comet cowboy !
PS: Freakangels is ONLY one I care about out of that group of adaptations.