the faster you go the longer it takes to turn around. which is sorta true in space for an airplane your nose has to always be in the wind otherwise your wings wont work. for a space craft you are free to point your nose any way you like regaurdless of your vector, but unless you fire your iengines your not turning around your just flying backwards. just try to turn an sr71 blackbird around using less than 3 state's airspace, its just not possible.
i find if you use a low rotdamp and a high damp it will give you more realistic physics. i remember when tachyon fans used to argue that tachyon's physics are better, i found that it had the same damn physics freespace had, only with slightly different values plugged in to the equasion. none the less you can do snap turns in freespace in this manor cause you can turn a full 180 and it will take a second or two for the ship to change direction. i think if you removed the speed caps the freespace physics would be really close to newtonian. you could aactually fake it by seting the maximum speed to the speed of light ang making your acceleration really slow. freespace's limited play area would kinda make this suck though.