From what I understand, the display of available missions under Reputation is limited in order to reduce complexity. High missions are arguabaly not very useful for newcomers. However, the current strategy is not useful for people who have already accomplished all of these missions.
Instead of showing the complete mission history and stop displaying new missions at a certain level, why not showing the current and last completed mission only? This would limit each category to 2 missions and further reduce complexity.
The above does not give any clue about the current mission status.
I think it would make more sense to show the the current and last completed mission only.