Hi there, apologies for taking a minute to get to this! Thank you for your comments and feedback. I just want to clarify though on where I may have said sissification is a hard limit? Apologies if I'm misremembering, but I don't think I've commented on that aspect.
The aspect of sex and gender for the game at this stage doesn't have a huge effect on the gameplay experience at this time. The scenario you refer to, being able to wear feminine clothes as a male little, is 100% doable! I think maybe the current shop is slanted towards pushing only in line with the player's sex, but I think it also makes sense to maintain in some shape or form a way of getting unisex/opposite styled clothing.
But still, that's some food for thought moving forward! I can't say it'll be my priority at this time, but maybe there's a way of evaluating the "masculinity" or "femininity" of a player's outfit, and that can be a tool made available to mod devs.
I hope this answers your concerns, and thank you for playing!