I was gonna let him stay, but not as the leader. It was between that and keeping him as a prisoner, and while he probably would've deserved some kind of punishment, I thought that it wouldn't really help anything, Clem wouldn't be the kind of person to do that, and it was really up to the community that knew him and was most affected by his actions.
Also would have locked him in the basement and tried to help him out. I feel like he just needed support after he was kind of isolated in a leader position and everyone was looking to him to be this pillar of security.
Exile. Too much bad blood after killing Brody. I might have let him stay as a not-leader if he had just traded Tenn's sisters (Emphasis on might) but after covering it up for a year, and then planning to give them Clem and AJ, and then killing Brody when he was afraid his secret would get out, exile was the only real option I saw. If he stayed in any capacity then someone would have made an attempt on his life in revenge. Hell, AJ blows his brains out no matter what anyway, but even if Carver's demonspawn sharpshooter child hadn't been there then someone else was going to try for it. Probably Violet, but I think anyone aside from Louis had at least some chance of trying to kill him.
I also would never consider killing him because, as horrible as what he did was, I believe him when he says he did it to protect everyone else. It was fucked up, no question, and the shit he did after was awful, but he really wouldn't have done it if he thought he didn't have to.
Exile was the only real chance he had at survival, IMO.