the only problem to me would be if you could cast an aoe spell and get sp off all of the mobs i'd see mages grinding in lower areas. sure they would not get as much sp per kill but if they got 50 a kill from 1 shotting a low mob and could pull 5 at once they'd get 250sp for a 1 shot kill. i like the extra sp for killing tougher mobs not being able to sit and kill a bunch of low stuff.

i am not opposed to the idea i just wanted to point out the negatives i could see happening.