I really hope they don't add enemy health regen again for TotK Master Mode. It made so many fights a slog to get through rather than more difficult.
I think your idea of different ways to spend light blessings is really cool! I think I'd also like it if enemies used more weird fusion combos. Like I don't really worry about enemy archers much in combat since I'm moving around so much, but if they were using keese eyeballs or dazzle fruit on me sometimes, I would have to worry more about positioning in combat or taking them out.