I am very encouraged with this update plan and look forward to it.
Others have listed this already ... (Mengy for example) .. Mechanic and Content.
The big thing I hope I am reading correctly in the OP for Ch.4, is data analysis and interpretation.
Two or more commanders arriving in the same system or area of space should not necessarily each discover the same things when they complete their exploration.
Each should leave with, both a common set of a core data and individually, different detailed data/discoveries.
All this is based on their own interpretation of the same basic 'honk' data that was achieved.
The fact is that, if a commander is willing to go out into the deep dark, then they are likely a commander willing to put in the time and effort, to learn and develop skills. In other words, the rewards comes from the work needed to eek out the critical details necessary to find the discovery.
Still on mechanics, the interpretation should then inform, what type of scan parameters to use next, by way, to further enhancing the data quality and thereby getting closer to a discovery.
Regarding content, i.e. discoverable items, features, natural phenomenon, and so on ... the common stuff should be easy, the less common more hidden and the true big discoveries, hardest to find.
These big "would ya look at this Whoa!" discoveries could be rare metals which would call for returning with your mining rig for example ... or get sold as a grid ref to the market .....
Another side scenario that comes to mind;
Commander 1 is the first discoverer of System A and indeed first mapper for Planets A, B & C there. But Commander 2 is the first to find "the big discovery" of hidden Guardian artifacts because Commander 2 has developed better skill interpreting his/her honk data.
S!
P.S. + Rep to Mengy also .... I very much share his ideas