Yes, the movie had flaws. There was terrible computer graphics, and the monkey was an awful choice. The inclusion of the monkey is how you know everyone involved in the movie is probably doing cocaine.
But the father/son relationship was really interesting. Will was brilliant but the father was distant. I also liked the way Dr. Smith manipulated Will, because it brought out the real strength in the father/son relationship. Also, the same guy who did the voice for the Robot in the 1966 show did it for the movie. That's kind of cool. Also, will the Robot shout out "Danger, Will Robinson!?" You know that has got to happen, or it isn't Lost in Space.
As for the original series, I enjoyed it. Of course, I only saw it on reruns but there wasn't really any complicated back story that you had to swallow. These people were all on a colony ship that got lost in space. How easy of an explanation is that? It's pretty much an invitation to make every episode crazier than the last, because anything can happen in an infinite universe.
My hope is that the new one borrows gritty elements from the movie and somehow fuses them together with the silly, comedic vibe that made the series worth watching (especially if you are a kid). Netflix has a good track record for making quality programming, so here's to hoping that it's good.