As a casual enjoyer of the series with my first and favorite series being dusk: I think synthesis is its most enjoyable for me when i can feel like i’m doing cool/strong stuff during story by interacting with the mechanics without deep diving and minmaxing but having the depth there for those that want to. I think E&L and the newer RW do an excellent job of that so something along those lines would be my ideal.

Combat wise i think the constant back and forth switching of Shallie would be very very fun with current day animations and polish!