Okay, 100 Mana on Taliyah's Q is Overkill
No, no. I get it. It's a spammable spell... but 100 mana when it's her first ability that she maxes? That's absolutely insane. Syndra's Q is similar to Taliyah's in that it's easily spammable but it's only 80 mana. Why not nerf the CD or damage on her Q?
's Q is the first thing he maxes, and is a spell he spams. It costs 120 mana per cast when maxed, more than most champions ults. Be grateful it's only 100 mana.
E is a spell on a 2.25 second without any cdr. It deals 150 base damage and has poor scaling. It costs 100 mana.
I think 100 mana is an appropriate cost for how powerful Taliyah's Q is.