Obviously having a spell that heals 3/4 of your hp would be entirely too overpowered. It would then make mob fights entirely too easy and throw yet another radical change into PK. The spells are fine as they are except for maybe being put onto a sliding scale like heal. This is only because I believe that there is a set value of hp restored on cure light, serious, and critical but heal's restoration varies. Otherwise, they're all fine as is.