Idea for the mission board based on what OP said:
- Default mission board view shows a random selection of missions as it does currently.
- The drop down filter for legal/illegal missions etc... should be expanded to encompass all mission parent types - combat, trade, exploration, salvage, piracy, mining, courier etc...
- Picking one of those filter options doesn't just filter the random selection, but instead populates the board with a full complement of only those mission types, which includes the ones of that type present in the default view.
Almost as if the default view shows a small selection of a wider availability of missions, AND it might go some way to alleviate the problem of board hopping (said problem being not that it's an exploit, but that it takes you outside of the game to get the missions you actually want).
Maybe then, since we have different boards for passenger and regular missions, move the illegal missions to the Black Market Contact tab - having different shady Mission Givers for the factions' illegal dealings, and populate the main mission board with only legal ones. Actually... I might mock something up on Photoshop.