Her progression was very different compared to the other women. First you would get a scene with her in the Otherworld, then a follow-up in the Real World. alternate until completion of game.
But at the same time a lot of her backstory as too why she made a deal with Neala was kinda glossed over. While UxL was a fucking scam and a half, it did give the backstory of her stepmother pretty much stealing her inheritance and casting her off to the lonely apartment where Dizzy lives and Peter uses as a way to place some of the women after their separation from their significant others, but nothing was build up from that which leaves a lot of room for original story if not content.
I do agree with Taboofan however in that the progression system that Nergal made was a good foundation, but there needs to be a bit more. It doesn't have to be a super branching arc where every decision changes her perspective, but something to notice is that there isn't much difference in behavior from level 0 to level 8 or 9. It just goes from reluctant to "I want to jump on that cock NAHW!"
In the Chilly's mod(i dont remember if is the same in the base game), neala explains that backstory, about the stepmother, the contract, etc. She was intended to be a second MC, thats why there is a highschool map.
I don't think it's a good idea to remove her either, she is the only one who interacts with the MC in the otherworld, it would be better if more events with her are added in the normal world(like the one planed with a bottle game with her ,sydney and dizzy), although is very ambitious and not more important than the problems from the base game.
You are right about fixing the progression, is too drastic and sometimes static (like flirt with syndey or mom in the dinner, it doesn't matter how much progression do you have, is always the same lines) and other ones are literally unfinished or bugged in the base game.
In my opinion, i think it would be best to fix those problems from the base game, and then add more content.