Spell Vamp; Quick Suggestion

Spell Vamp, and advanced Spell Vamp like Will of the Ancients, has one majour flaw: it is reduced from area of effect abilities where mages have area of effect abilities. Spell Vamp is ability based meaning it is restricted by cooldowns so even if the AoE restriction was NOT there it is still weaker than Life Steal since Life Steal has a much higher DPS, but removing the AoE restriction would have the stat more viable on more mages. Single target spell casters are more than likely an assassin, hence do not need spell vamp since it is a kill or die scenario, so backline mages would be the only class that would take spell vamp.

Right now I would buy Spell Vamp on Malzahar, Brand, and Vel'Koz. Why? Well Brand and Vel'Koz do not have reduced Spell Vamp on their passives and Malefic Visions is single target for Malzahar so they are champions where Spell Vamp is not dead weight on, but still not ideal.

Being resource and cooldown based is enough restrictions to Spell Vamp that it does not need reduced healing for being AoE where all backline mages are AoE; especially after the % value has been reduced multiple times over the years.