It could add a neat additional tactical element for enemy ships (or ships in a non-aligned planet's gravity well) to have limited line-of-sight as a kind of sensor range.  Hmm, not sure how this would work out though unless it was limited to stuff on the opposite side of a planet being hidden (since everything facing a fleet would be visible to it). At which point, does it really add enough to be worth doing?

Well, as to whether its worth doing it depends on how much of an issue you think it is that there's never any surprise when you enter a planets gravity well the idea in this case would be adopted within the open solar system format, so theyd be more scope for hiding things.

Stealth fields are something simillar are another idea?

Sensor limits right now with the current system would be mostly pointless. While simple line of sight makes sense the minute your fighter breaks over the horizon you would see all. It would end up being a nice reality feature that nobody would notice or be able to really use to their benefit.

We all could brain storm until the cows come home, but if the ideas aren’t possible to implement in the current game at this state it makes no difference.   What is possible along the lines free roam in the game? If it was implemented is there only one form that it could take and how much time would it consume to do anything else? In some cases it’s like shooting fish in a barrel not just whack a mole with the current system.  

Was the past system just jump lanes to every planet or was it different? My basic idea centered on increasing the stars gravity well to encompass the entire system. The system could be kept the same size or made smaller. If you think about it with a large system the amount of time needed to travel (w/o jumping) would offset the whack-a-mole problem. The time sink wouldn’t be much different and you could put your fleets where you want them in space and intercept if possible. Incoming fleets wouldn’t have to be a surprise if there were long range planetary sensors.  

Actually I was thinking something along those lines too. You could restrict the range of phase-jumps and with orbiting planets, distances between planets would change. So while your homeworld was originally within jumping distance of all your captured planets, half an orbit later, it is now relatively close to enemy planets.

This would also bring back the need for the extended phase jump range research.