Regarding 3: They do, use say an Akkan class capital from the TEC. It has to turn broadside to open up the majority of its weapons.
I think you need more play time

, they definitely do maneuver in 3 dimensions. But if you're zoomed out and/or watching two capital ships duke it out then you'll miss the movements that they do make. You won't see a capital ship trying to dance about like a fighter, all that moment to accelerate does not make for a nimble vessel

Watch the fighters and bombers for constant maneuvering, but bigger ships are basically just going to slug it out. Any tactical maneuvering falls under micromanaging their position and targets - which can certainly make a difference!
I agree with you on the tutorials though, even one that provided a true taste of actually setting up a successful first planet with tips as to what to build would be of huge benefit to new players I think.