I remember the days when abilities actually had a high mana cost.

But no one else seems to remember that champs like Lux were gated by mana costs making a 30 24 second cooldown on her ult actually limited.

Let us look at Lux for a minute and how she use to be greatly gated by mana costs.

Yes light binding use to cost 60 / 75 / 90 / 105 / 120 compared to the current 50 / 60 / 70 / 80 / 90 yes this would drain mana really fast and forced lux players to often abandon some armor and MR and get mana regen runes to cover this weakness and in turn opened up another weakness forcing lux players to have to be smart and safe.

Finales Funkeln (this name is still so much better) had a cost 100 / 150 / 200 instead of the current 100 at all ranks for Infinite Light final spark

Yes it was in fact enough to force a lux to have to back and get mana instead of being able to endlessly ult every 30 24 seconds just becasue she has Athene's

And you people wonder why Riot is nerfing the hell out of mana regen? It gives to much sustained pressure which is suppose to be a limitation of mages. No a Mage is not a marksmen which is the class that is suppose to have the best sustained damage. Yes back in season 2 there was CoH which would cover most mana issues at the cost of an extremely slot inefficient item.