Each planet could have several different objectives and bosses to choose from. The game picks a planet, and then a random order of maybe three objectives, and then a boss. The areas of the planet used could be different as well. Players could use their sparrows to go to the different areas sometimes if it’s on the surface. This would not only keep them somewhat fresh but it would actually utilize the planets more. Especially the areas that we only ever go into for story/side quests. Then, allow the possibility for it to go heroic for extra or special loot. I think something like this beats playing the exact same linear missions over and over where the same enemies spawn from the same areas every time and we defeat the exact same named boss for the umpteenth time.