Considering that the gravitational acceleration due to our sun at 1 astronomical unit is about 0.006 m/s2 I don't think you'd even notice the effects on your ship. Even in a modified simulation like KSP you need to jump the time warp up to 100 or 1000x just to let gravity drag you towards Kerbin or the Mun.
Then there's all the issues associated with not breaking the physics simulation with the speeds you are travelling. If we're expecting an ultimate velocity cap of a couple hundred meters per second, orbital velocities would have to be around a hundred meters per second at low altitude. This means your gravitational acceleration would have to be tiny to the point that again, I doubt you'd even notice it.
And unless there's a seamless transition between space and planets (unlikely) or between planetary bodies themselves (also unlikely) there's not much of a reason to have a gravity simulation anyway. You can pick whatever frame of reference you want to use, and for that block of space the gravitational acceleration due to any body would be identical, for all practical purposes, for anything within it.
As far as planetary movement goes you'd have the same result putting planets on rails as attempting any sort of physics simulation, plus you wouldn't be introducing problems into the physics simulation. What happens when your planet is moving 200 m/s and your ultimate speed limit is 300m/s? Your ships can only accelerate to 100 m/s relative to the planet forward in the orbit, but 500 m/s relative to the planet back down the orbit. That's assuming the star is the stationary reference frame. If the planet is the reference frame instead, you'd need a second reference frame that only affects the planet in order to simulate the orbit!
Long story short, I don't think we'll be getting any sort of orbital physics simulation. It's several layers more complexity for something that doesn't really add to the gameplay, nor does it seem to fit the style that BR is going for. If we're not transferring between planetary bodies at standard velocities, it's not even immersion breaking because in the void of space you wouldn't be able to tell.