I'm Guessing You are one of those that only reads the main titles so are unaware of the great many writers who have written Damian since Rebirth.
below are a few who not only did something different with him but wrote him to perfection.
Orlando
Esposito
Priest
mordeci
King
Seeley
Snyder
Tynion
Kelly
Higgings
Jurgens
taylor
Percy
Nguyen
Unlike a character like Jason who has had like 10 writers and the one story arc since he returned. Damian has been handled by so many and only bendis has written him out of Character.
Glass is a special case since he was mandated to write Damian in a manner that'll lead to him losing the Robin mantle so unclear what his normal Damian's like.
Damian is one of the more consistent bat characters and at the same time one of the more refreshing when you consider the sheer number of writers who use him and the variety of stories we have.
Bruce is dealing with the same truma and gotham is once again being taken over.
Jason is whinning about dying, dealing daddy issues and Jokers as per always
Damian has tried to change the LOA to good and has been overthrown
Damian has quit Robin after becoming the only Robin to truly attempt an actual alternative to Killing and batman's methods
Damian is an emotionally well adjusted batman who sews and has a loving relationship.
Those are 3 different Damian's in publication right now and all are an evolution of the character. can you give me just one other bat Character that is delivering such variety or that is showing such evolution?
Just putting Power Girl up there as an example. DC hasn't even really tried to do anything with her, much less done it.
No I meant Nguyen since he gave us batman tales recently. I was Only listing writers who have written Damian since 2016.
Jason has never tried to to find another option to batman's methods. He abides by the Rules hence why he has a bat symbol and uses non lethal Rounds.
It would be easier to list characters that they do know what to do with.
If we are talking about characters who would be very difficult to fit in to continuity based on their original incarnation, then I would pick: Kid Eternity and Prez.
Black Lightning - The character has been around since 1977, and has a popular tv show going on three years (not cancelled after one) and heroes like Deadman have had more runs than him.
Reading through all your thoughts here's the ones I agree with the most-
Jamie Reyes
Cyborg
Donna Troy
Ray Palmer
Power Girl
Tim Drake
Black Lightning
Deadman
Now I don't think that all these folks deserve their own solo monthly, but I think these are amazing strong characters that DC has just done a crap job of figuring out their place in the DCU. They certainly deserve some regular ink. But since it seems 90% of all titles are Bats/Supes driven these days, I don't know if they would roll the dice to put them somewhere.