Energy usage is too high, or maybe the energy regen is too slow.
Sustain is too low.
Damage is balanced how it is currently.
I also personally think her Q would be better if it did bonus damage to minions on a lower scale, scaling up to the max rank damage.
energy cost are high to promote an offossive use of her W (as it regen a good chunk of energy), if cost were low, she will just sat on it all game long
Proccing her passive regens her energy. If you weave your passive rather than just tossing your q out a bunch of times you'll be fine on energy. You can use q almost endlessly as long as you proc your passive.
