I realy enjoyed playing the nimbus arc and it is a bit unworthy to go there after and would be great if it can be a solid end game place, so What about making an Elite Nimbus map, to which only lvl 50 players that have completed the Nimbus Arc can access, the difference with the regular on would be :
-Huge increase of the Mobs stats especialy the objectives Boss, ( by huge increase ,i mean it will require at least a dozen of player working together to achieve the objectiv).
-Increase the rewards as well as adding new ones ( fleet marks , Contrabands , Schematics, MK XII ground items ... etc ).
-Unique item drops that can be exchanged for a unique ground/space set (like the Techs that used to be in Elite STFs).
the plot might be something like :
The ferengi alliance discovered a good amount of latinium on Nimbu's soil but all the pirates and thugs wondering there makes it hard for them to exploit the planet so they are recruiting privateers to go handle the dirty work for them
.