I think this is a good idea DHLF.
How about do it like this... start with just a checkbox:
[/] This system is explorable (i.e. you have to visit the system in game and scan it to see what is there)
Then maybe another checkbox:
[/] System map is complete (advanced scanner must be used for explorable systems).
Eventually adding features like this could develop into a real gold mine for explorers. For example I recently visited a system called Neits. This has:
4 stars, worth 1200 credits each
13 "high metal content" planets, these are worth 2000 - 4000 credits each.
1 rocky moon, these are only about 200 credits and not really worth the effort.
Total income 38,716 credits.
Would be great if there was an easy way of sharing this sort of information, though it would take a lot of work to get it right I think.
There is a nice guide to exploration here http://lavewiki.com/exploration