I think for me the further it goes, the further it moves from the romantic image of pioneering space exploration at NASA to generic sci-fi, and it loses something along the way. Going to the moon in tin cans while people back home smoked and wrote equations on whiteboards in the 1970s, with all the period costumes, cars, sets... while it's becoming more a CGI space drama now. Which I get--the premise is that it goes through the decades, but obviously as the decades pass and it drifts further and further away from 'reality' it loses that vibe it started with.