Yes, only a miniscule fraction was discovered so far. But it's 100% unorganized, greatly helping that figure.
You might have a look at a certain area of space - and you have no idea if it's pristine, semi-explored or an over-explored Tourist spot.
Forum knowledge for common areas will answer a few of those questions, other 3rd party tools might give a clue as well if other Explorers used them as well - but that's about it.
Allowing Players to make a qualified decision where to head - or not - is the key.
Currently you might take interest in a 45000LY distant cluster of stars, head there... only to find out the entire thing is 100% Explored. You just wasted 45000LY worth of your time.
That's my whole point.
Have an ability to "fill in the blanks" or locate pristine areas or patches of space instead of "nope, that was a dud" and waste your time.
You know a little common Sense help a lot. Let look at the Tourist Spots. A lot of players want to jump jump jump if anything they might use the discovery scanner but nothing more. They are on a timer and they pick the most Direct route. It should not worry you.
Let took at the most Travel areas Like we can look at Sol, Colonia or Sag A* Beable Point and nebulas and Neutron highway and we know the most direct route has been explored. How do you use common sense to explore those major areas? The Answer Never follows the most direct route.
Let take Sol and Sag A* which is 25,900 LY away from each other. When I was heading to Sag A*. There two ways of doing this.
1 I offset my course by 1000 LY or more away from the traffic areas then fly 25,900 LY (Not directly to your objective) found a point 1000 LY close to the destination I am heading to then fly to your destination. So From Sol to Sag A* 99% of the stars I explored has never been touched by anyone But I am flying in 3 locations. So my Trip might add 2,000 LY or more LY to the most direct route and I avoid high traffic areas.
2 Now the two Point travel. You randomly pick and know it would not be a travelled much. So that Sol and Saga A* You might add 5,000 or more LY in travel more the better. Avoid Nebulas and neutron stars and such. You might only have first Explored 95% to 98% of first explored. It is still not bad.
Remember we have 400,000,000,000 systems. Only 0.0075 has been explored. It has been for 5 years.