Dark Marine was doing very well as a Thrope, I hope he can tell me what needs nerfing to make him suitable for tier 2.
Its not easy for me to tell you what could be nerf on him. I think he is a more difficult class to play because he dies very quickly. To get the most kills yesterday I just calculated the movement direction of the enemy players to hit them. It needs a little bit skill to hit somebody with his normal shots, but with two hits the enemy is mostly down and I think thats ok. Terminators or heavy marines are killing him very easy.
I never found him OP. Maybe at first we should let him like he is and watching how the other players can handle him. Just my opinion.