I'm glad you enjoy the writing, and agree that the combat would benefit from something more. I actually had a short discussion about it not too long ago on discord, and had 2 ideas. One would be to replace the combat with something similar to a slay the spire style card system. The other would be to apply limits to how strong you can get, and rebalance based around that.
Unfortunately, either would require much too major rehauls, so generally it was agreed that the combat should really just be a mechanism for getting to the lewds. So more grapples, xxx attacks, etc. Maybe if I do a sequel/second remake, I could consider something more in depth, but overall, it makes more sense just to focus on the lewds/plot.
You're right in that requiring either male or female parts has to do with not having to account for a 3rd case with the writing, where the player has nothing down there, since that's something most people won't see. Again, if I do a sequel/another remake, that would be something to consider.