In reply to the OP, I pointed this out during Beta (or whenever we first had access to the entire galaxy). I even made a thread* in the DDF detailing how a pathfinding/exploration mechanic could function, but my pleadings fell on deaf ears.
It was quite a long proposal, so I won't repeat it here, but the pathfinding part consisted of systems beyond the bubble not being accessible by default. To open up a new system, an Explorer (who needs to equip with dedicated scanning gear and purchase/carry a limited number of nav beacons) would be required to triangulate the position of a target system by visiting a number of already accessible stars, and performing a Stellar Scan in each, whilst pointing their ship at the target star (they would need to find it in the starfield each time, so the ability to eyeball accurately is a developed skill). Each Stellar Scan returns spectral analysis data as well as distance, so matching this data at each triangulation position gives confidence that the correct star has been scanned.
At any point, an 'Exploration Jump'** could be carried out, but the more scans collected, the more accurate the Exploration Jump. If too few, then the Explorer would emerge several million ls from the star. With more, the Explorer would emerge progressively closer to the star. Scans from widely-spaced star systems help accuracy also - think of terrestrial surveying with a theodolite).
To complete the activity, the Explorer would then need to get within a certain distance from the target star after the Exploration Jump, deploy one of their nav beacons, and then activate it (at which point it becomes invulnarable like the other existing beacons).
The new system wouldn't be accessible to other commanders until the Explorer sells this nav data to UC. The limit on nav beacons (subject to cargo space) requires the Explorer to revist the bubble periodically to restock.
The proposal was more detailed than above, but that's the gist of it.
Some liked it, some didn't understand it, some hated it, but FD never responded, and I soon realised the it was too late anyway - players don't like things being taken away, even if it's the ability to disregard the 150,000 systems in the bubble and grind their way to the further reaches of the galaxy.
Then weeks/months later, somebody in the forums asked about the ability of visiting other galaxies (400 billion systems wasn't enough it seems), and it occured to me that if FD introduced a limited range galactic hyperspace jump device that could barely reach the Large Magnellic Clouds, my proposal could be implemented there, and those that like things the way they are could stay in the Milky Way and get First Discovered tags on the remaining 399,999,000,000 unvisited systems***
I don't hold out any hope that my idea will even materialise though. There are probably technical reasons that limit what FD can do.
* During a brief window when we could make new threads in the DDF
** An unguided hyperspace jump, without the benefit and safety of a nav beacon at the target star
*** Approx