Imagine your Smuggler gets to 50 and it opens up a possible smuggler route between Alderaan and Quesh. You hire a smuggler to do the run from a possible list and choose if you want to smuggle high risk goods or low risk goods. Or perhaps you want to go legit? You make a choice and get the route going. After a week (or three days), you earn resource points from the route that you can cash in for credits or gear. In addition, you get the chance to open a new smuggling route between Alderaan and perhaps Tatooine or Hoth for purchase? A weekly/daily event is flashing on the smuggling interface, do you want to click on it to see if it contains a reward, a quest or trouble? Do you need to start bribing officials? Is your noteriety rising too fast from being suspected of smuggling illicit goods? Do you want to expand routes with extra ships or crew?
To me, that would be a lot of fun, and its class specific.
But what about other classes? A similar mechanic for Consulars managing diplomatic corps for different factions, Commandos running military squads on different planets against imperials to shore up fronts and Jedi Knights running security operations to keep the peace. You could even link up these operations for alts or other players in game. Perhaps you could gain a bonus to your activities with a random weekly event such as visiting a planet?
This would encourage people to log in on a more regular basis and to encourage people to get other classes to level 50 so they can open up their own class minigames. Perhaps they could even start these at a lower level and expand them at class storyline intervals?