A couple things, your little summary of complaints is kinda pointless since you agree with them in the first line. Nida said that 99% (hyperbolic for the majority) of complaints were about her having a dick and not being submissive, to say the same thing another way in your own words:
A bulk is bemoaning yet another muh-dick futadomme
So that entire section can be safely ignored.
To the next bit pointing out CoC1/TiTs examples of content where you can back out halfway, while I agree from a world building perspective this is neat it's also almost a complete waste of time. This kind of content tends to be an all or nothing affair, almost no one is going to read through half a dozen pages of Kelt treating you like a fleshlight and then decide to stick it to him with the transformation. This is also an unfair complaint to aim at the person paying for the commission since by nature these things are normally paid for based on work load, it's rather entitled to expect them to pay extra for content outside their interests.
To close let's look at your more targeted complaints.
- About as nuanced as a brick to the face.
- Their fetish and general sexual inclination is their entire personality. (Every point I levied towards Sariel applies here)
- One note
- This is the anal and oral character!
This is fair, almost all her content is entirely sex focused. She gets a few talk scenes once you recruit her but it's still not much to go on.
Inarguably substantially more corrupt than demons but somehow not a demon.
She still has her soul so she's not a demon. Why is a bigger world building issue, the exact process for becoming a demon is kinda nebulous both in CoC1 and CoC2. Corruption is important but not all that matters, Kelt is another example of a character undeniably corrupt and even having a 'demonic aura', but still not considered a demon.
No player choice
- The player triumphing at zero hour? Nah
- The player confronting the offender? Nah
- The player even getting the option to reject the character and removing the quest? Nah
Kinda already talked about this. Also anyone who's seriously upset about having an unfinished quest in the journal, lol.
And don't get me started on companions.
- When the PC is addicted to Marble's milk? Multiple characters show concern and personality. Izma gets downright hostile
- When Lane is siphoning the PC's funds? Multiple characters can be the one to start the intervention.
- When Alexandria is mind controlling the PC? You have to deliberately seal them in their quarters to stop them from interrupting.
You have married wives in your entourage. Yet nobody does anything.
Again, wider world building issue. This kinda stuff went out the window the second the Kas romance option became a thing, I can't see why any of your companions besides Quint would stay with you at that point. It would add more depth to the world if companions reacted but that's seemingly not the direction they're going in, it's even somewhat accounted for given that her bad end (where the majority of the brainwashing happens) takes place during an extended stay away from the group.
TLDR: Your only credible complaint in my opinion is the lack of character depth which could be subject to change if they decide to commission further expansions. Most of your other complaints are tied to larger world building problems and are unreasonable to apply to one specific character.