1. No waveclear
2. Mostly Melee champs and a shortrange ADC that all have to go through veigar box
3. Rengar has to walk through box, blackshield, tristana ulti and jump, Lee can kick him out if he goes in(same for fizz) and GP can cleanse the stun. It's just a bad pick there.
So unless they win the early game super hard they have 0% chance to win teamfights,so they are forced to like 1/3/1 but then they have no waveclear and C9 will just barrel down mid and clear sidewaves with GP ulti if needed.