Should Gul'dan's mechanics find their way into League?
Gul'dan's gimmick in HotS is that he doesn't regenerate mana, but can use his trait, Life Tap, to sacrifice a portion of his health to restore his mana. His mana costs are very high, so he generally needs to do this often, but he can also drain life from others akin to Fiddlesticks.
Now, I imagine plenty of you will say "His mechanics don't fit, we already have health costs", but having a mage with mana costs and the ability to sacrifice health for mana would allow for said mage to take mana/AP items without inefficiency. Plus it's something League hasn't done yet.
Could this fit? Or is it unnecessary?
The way I'd do it in League is to have the "Life Tap" ability on the E slot, and instead of having a Drain Life ability, a mage with this mechanic would instead be given Spell Vamp by leveling up their E. I know Spell Vamp was a trainwreck to balance, but that doesn't mean a Champion with it built-in can't be balanced.