There's no air resistance in space you handicap, the only thing affecting it's maneuverability is the position of it's thrusters.
you would still want a symmetric (preferably radially symmetric) ship, because an asymmetric ship is a pain in the ass to balance when under thrust.
Not in deep space where there's no outside forces acting on it.
http://www.projectrho.com/rocket/basicdesign.phpscroll down to symmetry.
That's only relevant if the ship is in significant proximity to a significant celestial body; like a moon, star, or planet.
That's why there are OMS thrusters like on the Space Shuttle.
if thrust is not distributed evenly on a ship it will not go straight.on assymetrical ships, it is very hard to distribute thrust evenly.this is simple physics.
In deep space, where there's no gravity at all, the ship would move as one mass.