I think that the spinning core of the imperial cruiser keeps spinning during manoeuvres, this is a exclusive tech only found within the Empire, the inner surface of the ring have emitters that tap directly into Dark matter making the spinning core unaffected by Inertia, because of the abundance of Dark Matter the gravitational forces counter any Inertia.
NO NO NO NO

! Don't make me come over there and pound you with my mighty science hammer

!
You can't mess around with stuff we know about willy nilly- just made up stuff that doesn't exist

! Dark matter behaves like any other type of matter when it comes to gravity... that's how it was found. Scientists measured how fast stars were whizzing around the centre of their galaxy, expecting this speed to increase for a while, then drop off. They never saw the drop off
see here for an example.
The OP seems to forget that you can accelerate in any direction, so the ring will be parallel to acceleration at some point, no matter how you orient it, unless you deliberately swish it round!
I agree with the sensible consensus that the rings are mainly for doplamacy missions where the ship is still. During battle stations, the ring could either be spun down or just evacuated if the rest of the ship design is balanced for the spinning ring and stopping it would mess it up.