I've been putting some thought into this while I was away. I think it comes to that same idea of two ideas being fine on their own, but not working well together. I could easily have made some mistakes or missed things for this comment, as I still haven't dived back into the game again. I'm iffy on the threat the main villain poses. I apologise for how confrontational this post is going to be, this is not born out of malice but done in hopes of helping you.
Almost everything about the game screams broad appeal. The breadth of sexual content available, the amount of control you have over your own character's appearance, the game's mechanics, themes of exploration, and the general goal of pulling yourself up from debt but still having the option to quit at any time. Putting aside the tentacle pod and placeholder balance/mechanics, Iannan is the only thing that sticks out like a sore thumb. Here is a companion character that the player is forced to take on and she can't just be ignored if she isn't your thing. This character is central to the story and constantly commenting on various events. Unlike the PC, you have no control over her appearance, behavior, or a large part of her advances. You are going to get harassed by her unless you go out of your way to do favors, buy her a body you might never intend for her to use, and refuse to engage with her mechanics.
On the flip side, Iannnan herself feels kinda toothless. Her presentation is such that a player might feel like they should be trying to park the ship inside the nearest star or black hole as soon as possible, but you can also just choose to give up whenever you want. There's a mutual enemy, but there's nothing really motivating the player to go after him aside from revenge. Unless I missed something, he reads like a small time pirate who stumbled on the ship. He knew he needed to destroy Iannan, but wasn't willing to sacrifice himself in the process. Even the possibility that he couldn't negotiate an alliance or transport was too frightening to him that he didn't even try it. Better you than me. That's not evil, just cowardice. Iannna is far more dangerous, and is actively messing with the PC. She won't offer her robot body in the PC's place after you built it if the ship is boarded. However she won't actually do anything harmful unless the PC asks her to and can be easily convinced to back off. Isn't a big part of the bimbofication kink that it's forced?
I don't get the impression that Cloud 10 has a core theme or goal. It's being pulled in different directions that I don't think work together. I'd like to throw out two short game ideas:
Unity and Discovery: First, a game about exploring an unexplored region of space full of wonder and the ruins of ancient aliens. Our custom designed PC meets up with an ancient AI that takes on an appearance that offers similar if not equal customization as the PC has. This is the broad appeal game. The AI companion is clearly benevolent, either due to an inbuilt moral code or due to a pragmatic view that they're better working with natural intelligence rather than making an enemy of them. Perhaps they have difficulty trusting sapients that don't love them, in a physical sense, or show their desire for cooperation through open affection. The AI and PC have joined forces to deal with an obvious threat, with a clear negative consequence to more than just the PC if they fail and a reason why the PC has to be the one to solve this problem. Along the way they meet a variety of races which may or may not include sexual escapades which never directly impact the main game's plotline or mechanics. It's all up to the player to give permission first. They face various enemies, both natural intelligences and artificial intelligences, but prevail thanks to their cooperation between that natural and artificial. The AI here is a similar sort of character to Commander Data or EDI.
Desperation and Fragility: Second, a game where the PC has been stranded on an ancient alien station/base and implanted with cybernetics by an alien entity aboard. The old AI aboard is waking up, and is taking a liking towards the PC. Those likings also involve plans to change the PC, to integrate the PC into itself as a pleasure slave and an extension of its will. It needs the PC to carry itself to other places, so it can spread it's joy and integrate more minds, more sluts. The PC must scavenge the station, find a way to escape, while also fighting off the AI's agents, holding on against the changes that are being forced upon themselves, possibly even make a deal with the devil, and escape before they are fully integrated into the AI or succumb to the pleasures it offers. Even if you succeed, there's no way to escape completely unchanged. This is a niche appeal game, all about forced content, player submission, and bimbofication/slutification. This AI is more like SHODAN or GLaDOS.
The two of these are perfectly fine adult games. They are radically different, with unique game mechanics, story elements, and sexual content. Each of these feed into the central themes of the game and create a better whole as a result.
Cloud 10 has something like the mechanics and exploration of the first game, but the companion is the AI from the second with a watered down submission system. There isn't a greater evil that must be overcome ala XERXES and The Many in System Shock 2 that justifies the PC working with SHODAN (though admittedly something like that might be a good addition to the second game idea so the player has a reason to willingly let the AI into their head). However, Iannan would actually be totally fine in her current form, if she was an optional companion. Forced sexual content cannot work in an adult game intended for broad appeal unless it's in an optional quest/area that's clearly signposted or tied to a content flag.
EDIT: If she were optional, you could go absolutely nuts with her submission/bimbofication mechanics. There'd be no issues with her taking one specific form and constantly harassing the PC if you get her. That's probably the biggest difference between her and Hand So and ultimately why I have an issue with her.