Playing the way you want to will get you to pretty much L3 in each role, above that you will have to go out of your way to demonstrate specific skills. If you don't want to do it, you don't have to. I's prefer a 3:3:3 crew member in any role to a 1:1:6 gunner (who I imagine as screaming for his gun to be fixed/extinguished whilst not helping the rest of the crew to fix the hull and balloon whilst the ship bounces across the ground - been there, got the tee shirt, he ain't coming back on my crew).
I think you're taking the wrong tack. The community this game has is, for the most part, very welcoming and willing to learn. If a player is good at one thing, but doesn't act as a team player, don't write him off as a bad egg--teach him to be better! Common sense isn't common sense if someone doesn't get it. This isn't DOTA 2 here. Let's not make things toxic just because you couldn't immediately get someone to do what you wanted.
Crews in this game aren't a democracy, but they're not a dictatorship, either. Nobody wants to play with a captain that demands you ask "How high?" When he barks "Jump!" Our job as game veterans is to educate other players, to be the "community managers" in each match, each ship. If they don't listen to your advice, then yes, you're justified. But to just say "You're an ass" and refuse to play with someone, BEFORE you've taken the time to try and make them a better player? That's obnoxious.
The problem crews are those that don't listen. I take it you only ever play with an established crew never to have come across this problem. When your gunner sits on the fprward gun on a Junker and you ask him to drop to the lower deck for a bradside pass - and he ignores you, and even starts to complain about how he can no longer shoot anything?
I'm patient, I'll even start "new player" games to give some newbies a grounding to make up for the poor tutorial support and have been doing so on-and-off for a couple of months. But there's a limit to patience when the other player doesn't want to play as a crew/team.
I don't want even want a kick option, everyone gets the benefit of the doubt - but I have very low expectations of players with unbalanced levels. Captains need to gun to understand fire arcs, depression and elevation restrictions, Gunners need to understand engineering priorities, and Engineers need to know a little of everything and have a situational awareness to know what to do and when.