While cure spells getting better as the caster raises in level makes a certain kind of sense, but doesn’t adress why a cure light wound spell gets worse as characters advance. Granted a lot of this is simply naming convention, and if it hadn’t been called Light Wounds this might not be a problem. But it is, and so it is.
So I’m kind of kicking this idea around, but don’t know if I’ll actually go for it.
The idea I was thinking that what should happen is this. Casting cure spells should be relevant to the power of the target, not the caster. So a clw will still be awesome to a 1st level guy, but as they get higher, it won’t lose as much utility.
Cure I: 1d6+1 per level of the target (+0 for normals). Max of 1d6+4
Cure II (Moderate): 2d6+1 per level of target, max 2d6+7
Cure III (Serious): 3d6+1 per level of target, max 3d6+10
Cure IV (Critical): 4d6+1 per level of target, max 4d6+14
For a slightly more radical approach:
I: as above
II: as above, max 2d6+8
III: 2d6+2 per level, max 2d6+20
IV: 2d6+3 per level, max 2d6+42
The fact that cure spells don't correlate well with the abstract nature of hit points is one of the ongoing hot spots in every D&D style game. Your idea definitely has merit.
By way of response, I'll share my own "in-world" justification for how the cure spells work.
1. Cure spells are intended to be applied to characters that are already at 0 or less hit points, e.g., characters that have clearly taken a real, hard wound.
2. The more negative *any* character's hit points are, the worse this wound. Cure light wounds is helpful for characters that are only a bit below zero, but is less likely to help someone who is at -10 hp or more. In contrast, Cure critical wound can save the life of a greviously or even mortally wounded character.
3. When used on characters that are not actually brutally wounded (e.g. are above 0 hp), cure spells simply restore vim and vigor, close up some bruises, ease some joint aches, etc. A low level character is more readily winded and less able to deal with pain and shock, but conversely gets a relatively greater benefit from such. A high level character has a naturally high pain tolerance and has "been through it before," so he gets a relatively lower benefit from such. (E.G.: A band-aid is the same whether you are a kid or a special forces trooper. The same wound that will make a kid want a band-aid will make a special forces trooper sneer in contempt.)
Nothing above wouldn't work as a justification for cure spells based on character level, of course.