Vaynes Q should increase her auto attack range
It is little more then a low cd extremely short range dash with an unnoticeable boost in damage. I would say increase the range on the dash but that seems too OP, how about making it increase her auto attack range for her next attack? How much would be fair, +100 range? +200? This would help her with one of her biggest weaknesses, short range.
but a little anything to increase the area of her sphere of damage since it is so small compared to other ADCs.