Sustain Keystone for MAGES/Mana-to-heath mechanic for possible items

Where: Red or Green Tree, at the very top.

What: A capstone that grants a small heal-over-time on any mana expenditure, scaling with mana spent.

Example Keystone:

Mind Over Body: -When you use an ability (active, no toggles or passive-on-hit-effects)-, gain 25/40/55 (at levels 1/8/13) (+50% mana spent) health over four seconds. (This effect can only activate once every eight/seven/six/five seconds, at levels 1/6/11/16)

You might be a bit shocked. "Arakk!" you gasp, "That's like a free third of a healing potion every eight seconds, scaling down to five!"

Except with the removal of mana potions, this is far from free. There's essentially no way to turn that health back into mana. This preserves the innate advantage of manaless champions having one less resource to manage, but at the same time reduces the burden that their 'free' poke puts on a mana-bearing mage's health bar somewhat- giving mages a bit of breathing room to counterplay oppressive laning styles like or mid, however rare the latter may be. Both tend to have a poke basically free (shuriken and passive, respectively) that they use to clear waves and damage their laner until they're low enough to all-in. There's very little counterplay in the extreme early game- you dodge or move away from the poke, possibly being zoned off from CS, or you get hit and try to make it 'worth' by chasing a champion with a dash at level 2. A capstone like this trades the damage of Thunderlord's Decree or Deathfire Touch for survivability; it won't reduce the damage you take from an all in (yeah, still rush armguard vs Zed..), but it will keep you 'topped up' to increase your chances of surviving that first assassin dive on you.

Later in the game, its relevance becomes clearer for champions like and Aurelion Sol. The average teamfight lasts about ten seconds, give or take; with careful management of this mastery, an Azir player could proc it once 'getting there', and then twice in the actual fight- healing up about 100 health with each proc at level 13.

Next problem? Poke champions! And PLEASE NERF .

Okay so doesn't need nerfs, people just need to learn to play against him. (e.g. not stand next to birdswain). But what about those horrific poke champions? Those players. Those mains. (Satan). Well, the fact of the matter is- all of those champs have some way of avoiding (or in the case of supports like Soraka or Sona, healing away) damage in the first place that allows them to poke and get out without suffering from your retaliation. In the case of Xerath, his extreme range means you'll rarely touch him if he plays well. Lux has her shield, even if you try to poke her back with an equally-ranged ability. And Teemo, of course, has his Q- otherwise known as 'haha yes stand there and uselessly autoattack me, I'll run away right before you start hurting me'. In lanes where they have the advantage already, this mastery wouldn't benefit poke champions much at all- but against lanes that they would usually struggle with, the keystone would make it a little easier for those players to 'not feed', even if they don't get any kills (remember, there's the tradeoff of a damage keystone).

So the elephant in the room, now- I haven't forgotten about in the consideration of this keystone. In fact, Vlad is my primary reason for thinking of the MANA tradeoff component of this keystone- yes, he can still use it, but ideally the base heal providing only roughly half of the 'final heal', plus the cooldown, make its sustain effect marginal; Vlad already sustains for days, and this offers no damage. Xin Zhao seems like he might be a problem, as this stacks with his W and will probably be procced every time it's up if he plays around it- but why, WHY would he do that when he can take Thunderlords and make you startlingly dead by the third hit of his W? Last, but not least- Warwick. Natural synergy, he already gets tanky, this gives him even more obscene dueling potential and jungle sustain- mainly jungle sustain. But he already has those things, and the mana tradeoff means this isn't worth it.

All in all, I think this would be a healthy keystone and an excellent mechanic to put into effect, even if not as a mastery. I would love to see "X% of mana spent is gained as life" on an item, or "Gain X Life on Spell Cast"; I think these would open considerable strategic choices for both early game play and teamfights for sustained-damage champs who can't use Lifesteal (or can't use it effectively).

Red response please please please please.