Maybe I'm misremembering potions from 4e. I remember encounter spells just giving you back an amount based on your healing surge value and thought potions used the healing surge value too. Yeah, potions should give you that scaling amount so high HP character get a proportional benefit.Maybe I wasn't clear. I hate that potions burn your surge for a fixed amount of HP independent of your Surge Value. I love healing surges, but potions in 4e really suck IMHO, specially for defenders.
I think they should give HP based on your surge value, even if it's a fraction of it.