I'm less concerned with Barclay's idiosyncrasies than the alarming rate that the captains of Constitution-Class starships tend to go nuts despite the fact that they are supposed to be "the best of the best", and that many Admirals seem to become corrupt from the moment they gain their rank insignia!
Is it the rank insignia or the new uniform? Or is it more a matter of them being cooped up in offices all the time? Now that I mention it, I do have a hard time seeing some of them commanding ships. I mean, Ross? He's a good guy, but he's too indecisive to sit in the big chair.
Ross could have been a starship Captain in the past, but simply out of the big chair for a considerable amount of time, not unheard of as for example Picard, a very capable captain, did not have a command for nine years. Had Ross been promoted to Admiral only ten years before we first saw him, much of his experience would be out of date.
On the other side of the coin, Commodore Stocker had reached that rank without ever commanding a ship, and apparently not even serving on one, during his entire career.