I've discussed this before in other threads and made a similar one in the suggestions forum a long time ago.
Would make navbeacons a warzone, spawncamping: No.
Not to any greater degree than stations, or any place where players encounter eachother incidentally in normal flight. If these kinds of meetings leads to a slaughterfest, it is either because of a failure in how this system would be implemented, or it is because of a deeper failure in how players are led to interact with each other in the world.
For all random attempts at in-lore explanations using your cobbled-together thoughts on how you think the FSD works: Well, NPC's drop out at nav beacons. NPC's drop out at nav beacons and then leave for other systems. It appears to me, that at least currently, nav beacon serves as stopping points on shipping routes. You can explain away all you want, but NPC ships drop out at nav beacons from other systems, fly for a bit, and then jump on to another system.
For piracy at nav beacons: I think this should be a possibility, but not something greatly encouraged. The area of dropout would IMO be rather large (possibly also always a set distance from other ships), and of course, in civilized places, the nav beacons would be havily patrolled. Even naval patrols can't keep order at nav beacons? Then look: another failure that needs to be fixed. This feature is always doing things to help improve the game by highlighting the absurdities and problems.
I think you all can stop the ''Ermagerd is spawncamp like Eve'' argument now, unless you find a reason for why it would apply to anything other than the specific way you had in mind for how this feature would be implemented.
For the positives and game enrichments that would follow this feature: I think it would help with the pacing and feel of travel if there was a phase of normal flight between each jump.
It would obviously be an arena for ongoing events in the system: Activity at the nav beacon would mirror general goings-on in the system. It is a pretty handy way of making the player feel like there is actually stuff happening here outside the instances.
It could be a place for interaction with outposts, travelling merchants, dredgers, fuel stations, smugglers and mission contacts.
It would actually make travel through space where you are wanted a little bit dangerous.