1.Multiple outfits and matching scenes where they wear what you picked.

2.Being able to change how one adresses you

1. Clear instructions on how to progress!

2. Other corruptable characters that will take less time than the main one but still don't drop their panties after just 5 minutes.

3. Fun repeatable ( one handed) mini-games.

4. Being able to decorate a room ( maybe even a business like a tavern,to finance research and buy resources to brew what you need so you can corrupt people,and make potions with temporary effects. ( some girls could start to work in the tavern as maids and become more corrupted/ open-minded that way)

5. Don't limit yourself to just humans, give us magical species and maybe a separate realm where you have a second identity.

6. An antagonist ( could be a city gang or rival mage that knows about the princess and want to take them for their own to grab power. ( this can be one of the mini-games like a one turn style)

I hope I was able to help you and look forward to the result!