Melee vs Range with the Eternity Passive

I feel that the Eternity passive is balanced around ranged users. I understand that it was nerfed because many of these mages were abusing it by spamming mana consumption to regenerate tons of health. Given their inherent safety at a range, this was of course too powerful and the nerfs were warranted. However, melee range champions naturally take more damage, and thus could use the additional sustain. There are currently so few sustain items for melee range mages since spell vamp has been removed. Eternity and Hextech Gunblade are pretty much the only options at the moment. I honestly would like to see other items introduced, but I feel an adjustment to Eternity would at least help for the time being. I do not know what would be a balanced adjustment, but I would say by increasing the percentage of mana consumed converted to health by something like 10% for melee attackers. and of course increasing the limit to match, this could help to make up for the difference. I have also heard that melee champions already have a benefit by being able to regenerate more mana than ranged users. I would be willing to accept a decreased ratio on mana regain for an increase in health regain.