There is no reason at all, for vanilla characters I will add the ones required for the game story. For custom characters we are thinking a way to make a scrolled view for extra slots
I love the "catwoman" (all leather clad) heroine - I feel like the voices just fit her character so well.
As a suggestion just in general it would be good if you could have a bunch of presets you can load directly in the character creator. I'd wager most of your users dont want to spend an hour in there and the character creator - while awesome - is also quite daunting.
Having a way to load the existing heroines to tweak them , like just chaning a color, or hairstyle is one way to make it easier for people to customize.
And another thing I would add is a way to load a bunch of presets without having to download anything nor spend time on Discord, nor download them from Patreon. Something like a list of say 10-20 good presets that people can start with. Then, hopefully you could save "Catwoman" in there.
While I'm here I would also add as a new player it is a confusing experience to see the character from the title screen, which is also featured in Rob Cram's video and seemingly have no access to her.
If memory serves correctly, the girl on the title screen is the last one you 'played' with. And the Dev likes to make premade templates you can slot into the custom character creator and use... Although the download link for these templates appear to be a patreon exclusive perk, hence why you can't access the girl you're looking for.