A better solution is to simply give people more incentive to train weapon skills. I said it in another thread and I will say it again here. The game would be better if the main thing that determined damage was weapon skill and stats instead of what weapon you weild. If damage was primarily an effect of weapon skill/stats, and the weapon you weilded only had a small effect on the equation then the magic numbers although still relevent would not be hard breaks and there would be good reason to train your weapon skills past those break points.
while we're at it, how about give magic dart a power cap of 200, after all breakpoints are The Ultimate Evil(tm) and "we can always nerf it later"
I realize you were not serious, but I think the game actually would be better if the most damaging spell you got were your first level spells. Basically if it went like this:
Spells have no cap on spell power.
Freeze has the highest damage per spell power of all the cold based attacks.
Throw frost has a little less damage per spell power but allows you to attack at range.
Bolt of cold has even less damage per spell power, but allows you to attack multiple targets in a line.
Ice Storm continues the progression, but allows you to hit large areas.
This means that if you are facing a hord of monsters you would want ice storm, but if you just have one big bad in your face you would blast them with freeze since it would do more damage.