I didnt read whole topic, but first thing that came to my mind when I saw a few comments was
Planetary shield (or how you call it, meh)
I thought all planets have some sort of shield to prevent terrorist attacks like MOX bombing from space or not? That way, docking rings create "tunnel" trough the shield or something, so ships can dock without ramming the shield (and becoming huge fireball afterwards). Just a theory.
Only flaw I see in this can be the fact that rings were here before the shields.
Anyway, multiple docking rings could be very interesting, I would like to be able to dock from other side of the planet, etc.
Another idea - let the current rings stay, but give every planet an "invisible ring" which would be neutral to everyone, and serve as docking point for smugglers/pirates and other vermin. Commodities and equipment would be different in each docking point. For example, "smuggler's ring" (invisible one) would sell mostly contraband or buy the contraband, ordinary ring would sell/buy legal goods.
