Curious, Captain watter's seems to be one of the most universally hated Chars in star trek.
Even I can kind of sympathize with him, having gotten comfortable in his position, hoping that if he can Survive the mission, starfleet would be wowed enough to give him a permanent comission
(their probaly WERE some people as low rank as lieutenant commanding defiant class ships given how small those are.
He's hated because he's a douchebag. If you don't agree with him you get silenced. If you still don't come around to his way of thinking and kiss his ass then you end up in the brig. He's a dictator and would rightly have been returned to the Academy had the Valiant made it home.
Anyone with an ounce of humility, responsibility, and respect for the service would understand that he should have returned the Valiant to Federation space upon assuming command. He did not have the experience or wisdom necessary to continue the mission.