Kirk.. is more impish and interesting than I expected. He'll readily admit that his boldness is backed up by talent, and skill... he rarely shows that his mind has more than speed on its side, but it seems that he studies people because they're one of the few topics to give him some challenge. I'm starting to wonder if he chooses his crew on that basis.
That may be the difference between Picard's crew, and Kirk's crew. Picard is discerning, and chooses well, and carefully. Each of his crew was individually the finest available, the unusual jewels of starfleet. An engineer who had not just the right skills but the perfect eyes for the job, and a science officer who literally recalls every fact he ever encountered...
Actually, Data is the best example of Picard's choices. He's amazing for the job, can tell them anything.. but cannot talk with them. While he was my favorite character, and the best for the job, he and Picard had no chemistry, and learned little from each other.
Kirk instead chooses Spock, and creates a relationship that will forever challenge and change them both, and smash two cultures against each other in an interesting tangle of teamwork and battling wits. It's fascinating.