I'm wondering if those rating it down never saw the original series' or if they genuinely thought this was a poor follow up. My fear is people will skip watching it with such a low rating and it's still GOOD!
HBO did what HBO does and dressed it a little.... Weird. Yes. Not bad - but it's like talking to someone whose really smart and interesting, but their outfit would make Warhol say, "Isn't that a bit much?" It's a bit distracting.
Still, this is a good bridge from the 90's wrap up. Through the original 14 episodes we see slow progress, but still progress, over 30 years.
While I didn't always appreciate the artistic choices made for this, I think it's still a strong addition to the original series, providing a 60+ year time-spread of where we as a nation have grown, and where we definitely haven't.