Taliyah Changes: My thoughts.
This is just a rough concept that I have been sitting on for a while. Feel free to critique as needed.
Personally, i world love to see her kit revolved around a passive that involved X amount of rocks (a base off 3 to start off with) that rotate around her and block projectiles. These rocks regenerate every 9s ( not effected by CDR ). The cap on her rocks increases by one at 6/12/18, for a cap of 6 rocks total.
Her Q fires these rocks as a skillshot based on charges, depending on how many of the rocks she has around her. Each successful hit reduces the recharge time of the next rock by 3s, with a base CD of 9s per rock. This would give her a far more complex kit, however, it would give her enough utility and defensive capabilities to play on par with our aggressive mids. This ability is unaffected by CDR.
Her W should be changed slightly to give her a shield when used on herself, based on the amount of rocks she has around her. This would Consume all rocks and knock Taliyah into the air as if used on an enemy champion.
Her E would also reduce the cooldown of her rocks by 3s per enemy hit, capping at 2 rocks (18s or 6 hits).
For the R, when she lands from riding, she should create a circular minefield, similar to her E around where she landed. This gives her ult potential to be a semi-lethal ganking ability on its own, but still maintains enough counterplay. You'll still be able to see her ult, as per norm, so playing around it would be equally as important as it its now, but it gives it a more competitive edge than in its current state.