So we're all good with a scaly dragon woman but not a Gater Girl? What's the difference? Extreme sexual dimorphism could be in full play, like with the Bat Breeders.
If we look at the Bat Creatures as a species they are a species of humanoid bats. The males are more bat-like (animalistic) in appearance with arms that end in wings. While the female Breeders lack wings (instead they have fingers & apposable thumbs) & have a distinctly feminine, human-like body. Heck even their face is closer to a sharp features woman (if u ignore the big ears, bald head & shart teeth). And if u try to get a BJ from you're Breeder at lowest she will bite MC's dick off so she isnt exactly the safest creature until fully domesticated that is. The whole reason we keep her? She lays eggs that we can harvest for magic & potions.
Now let's look at the Gater Beasts. If we imagine the ones we have seen are all male specimens then we can work with that & have the females be more humanoid/feminine in build (with perhaps a less pronounced/lizard like face- mabey closer to an Argonian from TES) & have them appear in mabey a Nesting Grounds in the swamps. They could have an Alpha Male who allows them to make babies but anything else causes eggs to birth (no young- like most birds & reptiles who havent been fertilised). Dunno what potions the Gater Eggs could be used for (mabey Invisibility or Sleep Potions?) But I like the idea of a reptilian pet for the dungeon & it could work IMO if we follow closer to the Bat Breeders. Instead of using the Stun Spell mabey MC will have to use Syringe to catch one & then speak with Erevi about keeping her in the dungeon.
You might say "but shes a predator that will bite MC" so is BatBreeder AND Venomina but we got them on side eventually. Mabey MC will have to buy a Muzzle from Harold before he can safely let her out the cage.
For me it's their apparently wholly reptilian nature. YMMV, and I'm not looking down on anyone who would really like one.
Vixenatrix gets a pass from me since she's, y'know, a dragon: intelligent, able to carry on a nuanced conversation, with a mostly-human alternate form she openly says is used when mating with humans. The idea of banging her in dragon form, or mostly-dragon-but-with-tiddies, does nothing for me. As for Venomina, once things are worked out with her I never opt for nookie with her drider form, and don't see her for extra sessions even in human form.
Bat creatures class as mammals in my eyes; real-world monotremes are mammals despite laying eggs. And they appear to have some intelligence, perhaps on par with a great ape, the one you keep seems to develop genuine small-a affection if you choose that route with her. I don't see her for extra nookie, either. If females looked more like the males I'd almost certainly skip keeping a "pet" and make do with eggs from the caves.
Should Tinkerer find a way to incorporate female gatorbeasts where the ingredient or whatever they provide is necessary for advancing the Main storyline, appearing more human-like than the males, with the ability to "domesticate" them, I could be persuaded.