I'm sure we are all annoyed while we're using mana for spells and our lane enemy doesn't. What I suggest is an upper-hand chance for mana depending champions. It's like when there is a manaless enemy champion in 750 aoe, our champion should gain %75 mana regen. Numbers can be changed, but I hope you understand what I mean. Doesn't it be good?
The whole purpose of mana-less champions is to be able to stay in lane longer because you don't have mana costs on abilities to hold you down.
First off, for champions that take energy, they cannot spam their spells as much as mana-users. Their energy regenerates much faster than mana, but they have a very low amount of energy, so they trade quick regeneration for not having being able to last in longer fights while spamming spells.
Champions that use health for abilities sacrifice health in order to use abilities, which can be dangerous. I know that most of the champions that do that can easily regain that health, but abilities such as Vladimir's E cannot be spammed forever because of the stacking health cost, at least in early game. Also, a lot of them have longer cooldowns. Take Aatrox, for instance. Both his Q and E have pretty long cooldowns.
Basically, it's a fundamental part of the kit of these champions to be able to spam abilities. That's just how they work. Being able to use their abilities more often than their lane opponents is a very important part of their kits.
Something along the lines of When within 1500 range of a manaless champion, restore 1% missing mana every second?
