Spot some of the downsides of Shadow Hunter:
The interior is not really effective on the road
Low range: 550 => Easy to sell long legs, but typical Caithlyn
Inability to eradicate soldiers, large area damage
Depends on player skills
550 range is a very disadvantage for Vayne when compared to other gunners. The low passage phase, which is easy to push deep into the cylinder, will make it difficult for you and your teammates. Low levels mean that you will have to go deep into the fighting, where many enemies will endanger you.
Attack speed is low, no skill to destroy the monster will make this her defense is quite difficult. Despite the ability to farm well, deep push will create a premise for the opponent to come up with options before you. Once you are absorbed in solving the last hit of the car, the enemy wins the first dragon.