I dunno for now, but for a while changing class midgame didn't work. Getting wrong crew mix is frustrating, but you try to do with what you have (but wish for 1 pilot 1 gunner 2 engi crew).
People that don't jump-to when I tell them to do something AND don't at the same time tell me why they can't. That tends to tick me off.
If I'm a captain and give orders during ship-ship combat scenario, I expect my crew to either do it OR tell me tey can't (and what reason for). I'm reasonable. If you don't know where the said thing is for example, I'll probably be exasperated a bit if we are getting shot at, but I'll either send somebody else to do it or show you where it is.
No excuse for hitting the ballon instead of hull (or vice versa) with easy weapons (like gattling and carrorade) -except maybe not being entirely used of the ammo used (heavy or incendiary ammo for example).