1 - Resources. Planets taken are generally taken for resources. Once someone owns a significant portion of space it can be assumed that they have heavy influence over any planets nearby, eg, it could be considered that their government owns that area. Kind of like how the US owns Ca... never mind.

2 - Destructibility. Planets, save for non-canon creations, have always been protected against being destroyed. Would this same protection extend to space stations? This also brings up Weapons. About a month after I joined TRF Centerpoint was ruled as being ownable, but its gravity well generator not usable. If a station is destructible then it would make sense that its weapons would be usable, correct? THen comes the question of meterage, and whether or not a station should occupy meterage if its weapons are enabled.
3 - Movement. I'm not sure if this issue has come up yet, but I'm certain that moving stations could create problems in the future. It would be a great boon to the owner, and a pain for everyone else. Especially if weapons are enabled.
Personally, I think it should run this way. Stations generate no meterage, are destructible, have nominal defense weapons (no centerpoint uber crap), are movable, and should require a hefty extra amount of words to capture (as Rico did).
Opinions?