Of course, it's not just Spielberg behind this show. David Fury of Lost and Buffy fame as well as Brandon Braga who drove the Star Trek franchise into the ground until its recent resurrection are both producers as well. My guess is that Spielberg, having some experience in the matter, is going to handle the dinosaurs while Braga and Fury take care of the human drama.
Speaking of the human drama, the premise is that in 2149 the Earth is on the brink of ecological collapse. Thus, the brilliant scientists of the future send a family including some teenagers (yeah, that's smart) to prehistoric times to "reset" things via a rip in the time/space continuum. Wasn't this sort of thing already done on the British series Primeval?