Severance is an absolutely incredible premise, and each of the actors are perfect for their roles. I doubt the casting staff could have done any better with the choices they made. The Easter egg (if you want to call it that) in the first episode of season two is breathtaking, as soon as you realize that it is what you think it is.
Severance and Silo could probably rival Lost as far as storylines that could carry the shows for a long time.