Mages are supposed to be glass cannon. You're basically saying the few champions that are mages that can use it should have it taken away as a niche item for them/builds and to make it a standardized "Why would anyone not take it" kind of thing.
Riot's goal from what all the changes towards damage/less armor etc are showing is to make the games SHORTER, not longer, I really doubt they'd want another lane to have health regeneration of any sort and probably will slowly wipe it out of the other lanes/phase it until it's primarily jungle and bottom, which again seems to be the case. And then having champions like Olaf, WW, Nasus etc be the few champions that have LS into their passives, just like they did for silences. Making Silence a niche thing on champions like Soraka E and Garen's Q etc.
Morgana has a built in passive for Spell Vamp against Champs and Large monsters, just use her if you want that. That's a benefit of her kit, or use Vlad, because that's what he's all about is regaining health and prolonged battles of attrition.