Spell vamp
I think we should have the whole "area of effect spells only grant one third of the healing from spell vamp" gotten rid of. Compared to life steal there are very few items that give spell vamp in the first place. In addition to that, people are limited by cooldowns. If you're afraid someone like Akali will abuse it, fear not, she already abuses a bunch of other stuff. Life steal is viable on pretty much any champions, but spell vamp as it is is viable on very few and it's not even that great. It's a chance to make an entire stat more useful.