I see what you are trying to achieve with the Newtonian physics model, but I feel it doesn't work very well with such densely packed sectors. In the real world asteroids are thousands or even millions of miles apart even in the densest parts of the solar system, but in Avorion they are typically less than 1km. You *need* a nimble ship so as not to pancake against every chunk of space debris. In my experience, turning and thrusting to slow down inevitably causes some sidewards motion quickly resulting in a collision. It just doesn't work. You quickly realize that the only sensible course is to stack thrusters until your braking thrust is at least half of your acceleration thrust, and even then it is risky.
If you consider the X games, which I have been playing since XBTF, the sectors are similarly packed to Avorion but the speeds are much slower. Instead the player has the means to fast forward time such that they don't get bored moving about but at the same time they don't end up blasting through sectors at suicide speed. While I don't think this solution is a good idea for Avorion, the lesson is important.