I have no interest in making generic rubber forehead humans.
As for the lack of FTL, I already did make a world for an earlier project that lacked it. Several great dynasties ruled the stars with an iron fist. They would spend time in cold sleep for several decades, wake up for a year or two, sleep again, wake up, continue. As a result, they would be able to enact plans that would take centuries to come to fruition. Meanwhile, the commonfolk lived as pawns for the families that had outsmarted time. Interstellar travel still took decades, but that was nothing to the nearly immortal overlords.
You can make an interesting setting without FTL travel, you just have to think outside the box.