I know it's been potentially already pointed out in btrl wihlist in the past, but having g effect when turning too strongly for too long time would make the screen get red/black depending if you are on positive or negative g.
I know some will point out that it should not happen into 0g environnement, i would say : that would happen, scientist plan to use ship's rotation to simulate gravity. With the same mechanics a very strong turn would produce g effect too.
That won't prevent ai with circle fight, but it would fix the multiplayer issue.
About cockpit view, it would be good to have some small headmove simulated (like you have in racing sims (rfactor/gtr/gtl ) it would give more sensation to be a pilot than a camera 
for example : When you accelerate , the view get a bit backward and when you slow down the view get a bit forward too. (same for turning and afterburner)
I don't know how hard it would be to implemant, but i think it'll give qui good feedback to the player.
G forces are completely independent of gravity, being due to inetria and momentum, so all g forces from accelerations (rotational or translational) would be felt as on Earth - the only big difference is that while flying straight and level, there would not be the "background" 1g from gravity; all other sesations would be the same.
I like the idea of the first-person perspective shifting slightly with hard movements of the craft - it would make things far more realistic. How easy it would be to implement I have no idea. The thing is, it would need to be proportionate to the amount of control input. That's no problem for using "turbos", thrusters or reverse thrust, because they are all binary in application, but roll, pitch and yaw inputs are variable, so their reactions would need to be proportionate. It could also get out of hand where a high g loop results in several head movements, including a slight rotational head down movement from the vehicle pitching before the head starts moving and the sunsequent translational movement of the head downwards towards the seat under the g from a turn with forward velocity, while a pitching movement while in glide or stationary would require only the head tipping movement, but no vertical movement, and yaw and roll movements would need the perspective not only to shift slightly towards the outside of the turn translationally, but also a little rotationally to simulate the bottom of the pilot's head being attached to the neck while the top is more free to move. Complicated... As for black/red outs and g-LOC, they should be mandatory on multi-player, but again, the g-forces have to be related to pitch/yaw rates and speed together, not just rotation rates as you don't get any g-forces from a pivoting craft with no speed/in glide unless the cockpit is a long way from the CoG.
Less shake from the "turbos" would be good, too - it was much too rough on BTRL (and unlike any view on the show), and a small percieved head **** and tilt aft would be far more convincing and less distracting.
Anyway, I'd like to hear less inane chatter on the radio than the BTRL demo. Plenty of operation chatter, warranted expletives (frack) and some banter is fine, but BTRL laid it on far too thick.