-B's maiden voyage was a disaster, and I blame Starfleet far more than I would Harriman. The ship simply wasn't ready and it was unfortunate that an emergency situation cropped up right then and there. Harriman knew that--and that was the cause of his apparent indecision, IMO--but like any Captain of the Enterprise
, he responded when there was lives on the line. Harriman's discomfort was intensified by the presence of Kirk and so many press watching his every move and recording it for posterity. The one thing Harriman might have done was get all non-essential personnel off his bridge, including Kirk.
It's not canon, of course, but the novels have generally said that after this maiden voyage, Harriman grew extensively from this experience and eventually became one of Starfleet's greatest captains during the timeframe of the late 23rd-Century/early 24th-Century. They even went on to say that Harriman was involved in the Tomed Incident that led to the Romulans avoiding further contact with the Federation for over 50 years...
Very good points.
I also think that starship captains have to be engineers of some sorts too. They have to know generally
how their ship works so, while they may not be advanced specialists like engineers are, they do know how to swap out basic control circuits of various systems in an emergency. Picard, Sisko, Janeway, and even Archer were all seen occasionally removing an access panel to some system and doing a little emergency mechanical surgery every once in a while...