I have to wonder how well Lt. Morales' kit would work in League if it were adjusted

I imagine Riot would want to steer away from her kit due to their "manaless healing is toxic" policy, but let's just humor the idea for a moment. Lt. Morales is the best single-target healer in the game in HotS, but this comes at significant costs: she has no mobility, is easily killed, must stay within a reasonably close range of an ally to heal them, and has very little offensive presence. Nonetheless, she is excellent at sustaining allies for long periods of time, though it's in a game where the laning phase is very short-lived and gold farming is a non-factor (it doesn't exist in HotS).

I have to wonder how well a manaless healer could work in League if it were given significant drawbacks (i.e. lower power, very poor survivability, no mobility, etc). I do suspect that there is nothing Riot would do to allow it to work and that they'd just veto it immediately, but it's still worth theorizing over.