Manaless champions can be more like Dawngate's champions?
I'll admit, I'm a bit of a Dawngate fanboy. However, I do think that Riot could learn something from it. Particularly with regard to their manaless champions. Of particular note: making them have decently long cooldowns so that even if you 'can' spam everything, you don't neccesarily want to remove one of your tools willy nillly. (Of course, in Dawngate, everyone was manaless, so they got off easy because everyone was balanced in this respect, but still the basic idea should apply.)
The most ready example of really poorly balanced cool downs is
Yasuo's dash, which, while it does have a cooldown on a single target, it has virtually no cooldown while in a lane or team fight. So, there's absolutely no reason not to just spam it since you will always have it up, and never run out of resources (in fact, he technically increases his resource by just spamming it). I mean, it wouldn't even need to be a long, even even almost moderate cd, but just a 2 second global cool down on it so rushing in with w isn't 'completely' risk free.