I feel crossclass healing spells should have percentage scaling in the same vein MP scales with your level.

Pre HW content when you sync down stuff like Cure/Physick at lvl 49 heals a decent chunk per cast.

HW content at 60 or even early 50's? Decent chunk of healing is beat down to nothing. Instead of healing 1/10 of your max HP it is healing for around 1/30 of your max HP.

And yet the MP percentage per cast scaling is still there. You use a spell that costs MORE to do LESS for you.