The Orca may seem to be slow turning on first impression, and it is indeed a bit slower in the roll and pitch. However, load in the 6A thrusters, and try your YAW (left/right turning). It is faster than many other ship's pitch (up/down). It is one of the only ships that fly this way, but once you get used to dodging to the side, it feels much more nimble. Just be careful on your first few docking attempts, especially if you like to speed.
That style of flying also catches other pilots off guard: when doing a joust in a Ramming Orca, you roll so that their pitch is your yaw. They often assume they can zip close past you, but you suddenly swing out like a baseball bat and smash them into flinders.