This game format is way too hard to make it feel like choices matter. Its story driven more than a player-driven one.
Here are some suggestion that you can consider:
- Some decisions will make the LIs be more corrupted and kinky - Leading to BSDM, 3some, 4some, be part of Harem etc
- Some decisions will break the LIs heart so much that they decide to keep away from MC. eg, run away alone away from MC and the cast or suicide.
- Some decisions may lead to death of LIs
- Some decision will lead to a bad ending . eg MC died or one of the LIs joining the enemy
- Some decision will help you gain new allies or make some allies betray you etc
I'm not sure why you say its hard to make the choices matter in this story. While i can understand the MC will get corrupted regardless but the outcome can be different depending on the choice he made. If you tell me you dont have the manpower to develop multiple paths, its more understandable than saying it hard to make choices matter.
Try playing Deliverance from 1Thousand. He nailed the game concept. That game is a good reference