So Riot removes necessary mana costs from some champions and not others but there's no consistency
All of these are skills are ones that the champions need to do anything in a teamfight. Kog'maw and Tristana do pitiful damage without their steroids, Kayle is pretty useless without her ultimate, and without their steroids and Jax and Singed get chain CC'd and bursted before they can do anything without their ultimates, etc. And to top it all of, Singed's ultimate gives him mana regen but... it costs a lot of mana...
If you're going to start removing all of the mana constrictions on some gated champions can you start doing the same for other champions? Since Season 3 you removed Vayne's, Annie's, Kog'Maw's, Tristana's, etc mana burden completely with lower costs and higher mana pools and what not. Why can't you do the same for other champions? Why does Singed's ultimate cost mana if it gives mana regen? Why does Jax's ultimate cost mana if Kayle's or Riven's or Tryndamere's cost nothing? It's not like Jax's ultimate is better than theirs. Why does Olaf's Q cost 60 mana at level 1? It deals 10 less base damage than before the rework, it costs more mana, and you can't even instantly pick it up anymore. You removed the mana cost on Olaf's ultimate when he got changed but there's still so many cases of this. You can't just start removing mana costs on key parts of champions' kits and then not do it for other champions. You made Malphite's W cost 25 mana a few months ago from the insane scaling cost it used to have, which is good, but there's still a lot of champions that are being screwed by their mana costs, and this is why.
Champions (mostly melee champions lately) that have actual mana costs in lane like Singed and Jax and Olaf can't afford to start Doran's Shield because their mana costs won't be covered at all. If they start shield what happens is that you blow their mana pool trying to even engage the ranged champion. Jax Leaps and E's for half 1/3 to 1/2 his mana pool, Olaf Q's a few times and his mana pools dead, etc. Basically this means that the Doran's Shield buffs are only going to make the disparity between champions that don't have mana issues and champions that do have mana issues even bigger than it is now. Champions like Jax, Singed and Olaf would LOVE to start Doran's Shield against ranged champions but they can't because then they can't do anything in lane other than facetank hits. They can't use spells, they can't engage, they can only hope that shield blocks enough damage.
Last year you halved the mana cost on Nasus's Q at max rank, this VASTLY increased his sustain and lowered his mana issues later. Why can't you do the same for Olaf's W? In fact, why does Olaf even have mana? To gate his axes? His Q is the only still that even costs mana. Next time when you rework Olaf (which you should, he's still abysmal), just get rid of his mana pool and do what I think hashinshin suggested a year ago: give him an axe meter for a resource. "Olaf regenerates X axes every X duration. Blue Buff increases axe regeneration by X%".
Tl;dr you can't remove the mana costs of key skills on some champions and not others. It just makes being manaless or not mana burdened even more of an advantage. Champions like Jax/Irelia/Singed/Olaf would love to start shield but they can't because then they have no mana to do anything, while champions like Nasus and Malphite have the option of going either (since no decent malphite relies on Q in most cases top lane anyway).
