In my hands she feels pretty fine to me.
Laning phase, use Q one or 2 times on unworked ground to clear waves, rest of the time use it on worked ground, leave unworked ground in case of trading needed.
If you managed to pressure your opponent good job, you have the advantage, easy roams, easier to farm. If you haven't well, gotta use Q on unworked ground more often and shove wave to get farm, if you ever get the chance roam, easy ganks with ult etc etc.
You mention that she can't do dmg without specific items..... well that goes for every mage. About 100 ap is all you need to be able to one combo rotate to kill someone as a mage at lvl 6 v lvl 6 assuming your opponent didn't rush and MR. Taliyah since her ult doesn't do dmg would need 1 rotation + 1 more Q usually, and it's on a pretty low CD so it isn't that long of a wait.