Sounds like you'd like healing to fortify health instead of restore it. That wouldn't be hard to do: just change the spell effects. I kind of like the idea of healing causing a magicka drain that doesn't automatically regenerate. Kind of like swapping magicka for health. Would help curb the spamming. When I play, I use a mental rule that says I'm not allowed to use a healing spell or potion more than once/injury. It helps keep combat a little edgy.
But lately I've been toying with the idea of creating a new immersive healing menu that works like the repair menu (also like FO3) where injuries are location-specific, with each body part accounting for a portion of the total health. When a limb is injured, the player acquires a handicap (like an attribute drain) the amount of which is set by the amount of damage done to the body part. This attribute drain can be 'healed' when the injury is healed and is also restored over time via sleep, etc. None of this is new (I think it's basically a recap of an existing locational damage mod, but I can't remember which at the moment) except for the menu, which has some additional advantages:
1. When the player pulls up the menu, they see an icon of the body part and how much damage has been done to it, just like the repair menu. The player can then use a healing spell on the injured body part the same way they use a repair hammer. The amount of healing is then restricted to the damage done to that part. Alternately, they can just 'heal all' and the amount of healing is spread over the entire body, healing a portion of each injured limb.
2. If they don't have any healing spells or don't want to use them (for role-playing reasons) they can use first aid instead. First aid requires bandages (1 per injury) and restores an amount of damage determined by the player's armorer skill. (The reason why I pick this skill is based on an assumption: any experienced fighter is likely to know how to bind his or her own wounds just as they can repair their weapons and armor. The restoration skill can be reserved for magical healing.)
Using a menu allows for an intuitive method of treating injuries that gives the player something they can 'see at work' instead of keeping everything scripted behind the scenes (though that would work, too).
Alchemists could create healing salves and ointments that only affect one hit location at a time. These would be easier to find ingredients for and create, but do less overall healing. Healing 'potions' could be restricted to performing 'heal all' effects: more overall healing, but can't be used to target specific injuries. I would also restrict the healing menu to non-combat so the player can't heal specific injuries while they're fighting, but could still use potions and 'heal all' healing spells.
When it comes to diseases, I think that cure disease spells and potions should be restricted to curing a
single type of disease. Players would then have to learn spells or find alchemy ingredients for each specific disease, meaning you'll likely be stuck with one for a while until you find 'the cure'. I would also love to see specific screen effects for different type of diseases like Abo's realistic healing.