I last saw the shows just about a month ago so it's more recent in my mind.
I agree that Ronny Cox is a great actor and supposedly a really nice guy in real life. Maybe he feels he has something to make up for since he is usually portraying jack-asses. I think Jellico did get a bad rap, less so for his command style than by the resistance he got to his changes. I did get annoyed by him bad-mouthing Riker so soon after taking over, and then there was the "Get rid of that fish," comment. Clearly, he was written as a putz, but I did give him full credit for the rescue of Picard. The character should have gotten more appreciation in the end.
"Stop it? I'm counting on it."
"But not because you threaten me. I'll pay you because... it's my pleasure."