A couple such systems that I would like to see:
A nanomachine infested system.
The system is full of leeetle tiny ships. About the size of a recoilless cannon round, or smaller. They hunt in packs. They fire nano-damage weapons, which home in on you. I think this would look really cool, be really hard, and fun to play through. The idea for this came from my fiddling around with little tiny seeking fragments. (see the 'fossaman needs another debug' thread in the shipyard) Some sort of station near the center of the system could be spitting out new nano-fleets every few minutes. These ships would be incredibly easy to destroy...if you can hit them.
That idea might be better suited as version 2.0 material. But the mechanics for implementing something like that are in place now.
An alien derelict system.
Filled with lots of old, abandoned looking alien-type stations. Has turrets and other automated defenses scattered around. Near the entry stargate is a commonwealth research facility, which gives you missions for specific items to go and look for among the debris. They could give you alien weapons as a reward. (note: this is why I was asking about dock-screens as gate-jump initiators. The only way into this system would be through a military checkpoint station)
If someone feels like linking to the old thread on the UTF, feel free...I feel lazy right now.
I think the biggest ideas from there were black hole systems, supernova remnant systems, a commonwealth proving ground, a university system...I'm sure there were a few others.
