The premise was quite intriguing – an early interstellar mission returns to earth after 800 years, with the original crew (due to suspended animation and relativistic time dilation), only about a third have survived – to find Earth has radically changed.
There are a lot of unanswered questions, and areas where there seemed to be foreshadowing with no real payoff. I agree with the other commenters that this seems like the opportunity for a sequel or even a series to answer these questions.