Re: Dr. Leonard Horatio McCoy (DeForest Kelley)
You're absolutely right about Kirk trusting McCoy's judgement. McCoy and Spock complimented each other perfectly - Spock with his logic and McCoy with his passion and no-nonsense attitude. Each gave Kirk something different and together all three of them made an inimitable team.
As for Kirk always leading the away teams - that wasn't the prudent thing for a captain to do but I attributed his actions to Kirk having an enormous ego and a constant thirst for adventure. The day-to-day minutiae of running the ship didn't fire him up and he trusted his crew to do what needed to be done. I think Kirk was a old-school swashbuckling adventurer.