You guys are almost literally trying to turn apples into oranges.
If you're creating a new universe with new laws, you have to abandon pretty much everything and start fresh. No working with weak forces, no working with strong forces, ditch the ideas about gravity and such.
Firstly, the "equal and opposite force" law still applies.
Secondly, the Aether exists. The Aether is an array of particles (possibly static, with some neutrino-like qualities) through which solids in the universe move (if moving in the first place). The resistance of the Aether on any solid object is increasingly proportional compared to the size of the object. Thus, planets and asteroids slow to a non-orbital halt, and a large ship, despite its mass, comes to a halt just as quickly as a smaller ship moving at the same speed. Weapons, small and fast-moving, slow very little relatively, and are seen to travel long distances before they eventually slow and fizzle out. Their shell likely remains, of course, but that's a matter for the navigators.
Liquids, as a state of matter, tend to nullify the Aether, while gases and plasmas tend to displace it almost like a reverse form of gravity. Land vehicles aren't fighting two forces at once, and thrusters work perfectly well in space, without needing a small amount of time to ramp up.
Matter tends to clump, but thanks to the Aether Law, only up to a certain point. A large object such as a planet would have a great deal of resistance exerted on it, making it incapable of "clumping" with its sun - it would appear "locked" in space in a particular position.
Asteroids are formed, of course, by dust and small, non-asteroidal rocks. Instead of being molded by traditional gravity, they are instead molded by small impacts, and the clumping dust forcing everything ever closer to the planet. The amount of force required to cause one particle to bind to another is low relative to our universe, and happens much more easily. Anything formed through these methods (such as asteroids) still has a degree of non-displaced Aether within them, which gradually slows any rate of spin to a halt. If a large body contains large quantities of liquids, however, it does have the capacity to move, but only when an external, non-clumping force acts upon it. One might almost question why planets don't move again after their interiors become molten, but at that point they've already stopped moving, and the amount of force required to make them start moving again would be incredible thanks to their mass.
It probably has some flaws, but it seems to work at first glance, and it doesn't require you to force-fit laws from our universe.
Also I'm sure there are a large number of interesting implications here.