The best captain? I'll bullet down something from my little experience, although you did cover most of it already:
- At the beginning of a match, divides roles but not too strictly. It helps the engineers to know when to maintain/buff their lot and when to help the other engineer. Also, tells what the loadout is for, like "Yeah, I went for sniper build, so feel free to potshot all you can."
-Tells you what target he is aiming for, which guns to man and when he is going to use some pilot-skill. Generally being informative about what he is doing, even if with three words. Gunning is immensely helped when you are warned of a quick turn and that you should man the other gun.
- Knows his surroundings, or asks the crew to spot something he can't see.
- Acknowledges good engineering work when he gets it aboard. I like being the gunner and his work is pretty visible, but it is easy to forget the two other guys running around arms flailing to keep the ship afloat.
-Has some humor in what he/she does. It is always nice to hear the captain giggle after the other one blows apart, and some simple comments like "Well, I didn't see that one coming.", "Woops" and "Sic em!" create an certain atmosphere.
-FLIES the ship, not flails it. I hate it when the pilot does sudden turns and dives when I am trying to land a shot. Also, knows the lines-of-fire of his weapons, so he can position the ship correctly. Of course, telling us what he is doing helps.
All in all, I like a clearly communicating captain over a mute one.