Meanwhile ez can spam q every 2-4 seconds no problem, actually I can go on about most every ADC and champion being able to spam abilities non stop, yet Sivir Q costs more mana than everyone ults.... Oh btw she also has terrible BASE mana/regen. I mean sivir is a wave clear bot, she is terrible at most every other aspect of an ADC has the lowest AA range of them all as well.
PS while we are at it MF's is much in the same boat having absurd mana issues co9mpared to every other ADC as well and being a terrible duelist and pretty much limited to "pressing R".
I get it they have their "roles" but i dont also see why they are also the 2 most mana starved champions in the entire game, MF crappy make it rain takes 1/3 her mana bar at level 1 lol, it does terrible dmg, and has a medicore slow, I can list off far more powerful spells on shorter CD's that take less of the champs overall mana.
TLDR, Sivir and MF deserve some mana QoL buffs.