Ahri's E
In my opinion Ahri's E should make her target take 20% more damage from all types of damage from Ahri. It'd be a nice small addition to give Ahri a little more damage from her AAs. I guess it's not a super necessary thing but it'd be a nice little buff, so Ahri can do a bit more damage while her other spells hit (as in all fox fires and her orb on its return path). And since the charm remains on enemies for 6 seconds, it allows pre-6 Ahri to be a little bit more of a threat once all of her spells are down. Plus I don't really see any reason not to as Ahri isn't over powered currently, and this is only a slight buff.