The game has a ton of content already, they've just set us on a very narrow path to experiencing it.
My solution? Have all the planetary side-quests scale to the player's current level. Make bonus-series quests unlock when you complete 100% of a planets' content, and have them be repeatable and award daily commendations.
Players want to feel like they have choice, and they need a reason to revisit their favorite planets.
It has a lot of generic content. I wouldnt say a ton of content is what this game has. It is lacking in many areas.