Taliyah W doesn't work sometimes...
Besides the delay in the cast animation, there is the actual speed at which the player can actually cast the ability in a controlled manner. Trying to press W too fast sometimes seems non responsive. Pressing it too fast also means less control in the direction of the W.
On the other end, taking the extra time to cast it right leaves too much of a delay in actual game play making it obvious to enemy players. This gives them plenty of time to react.
On top of that, compared to Vel koz E, the Taliyah W is about half the size, making it much harder to land.
Why this is bad is because her minefield E, is almost useless if her W does not land. Her ult does no damage and her Q is unreliable and low damage too.
I get that this champ can block escape routes, but so can 
, but the rest of his kit is not crap because of it.
