My undergrad synoptic professor (the great Jon Martin) really liked the NGM because of how it smoothed out vorticity and vertical velocity fields, so you could see the quasi-geostrophic equations in action without all of the noise from mesoscale and convective stuff. I remember when the retirement announcement came out he gave a little speech to the class about how the push for higher res wasn't the be-all, end-all. Of course this was the era when the 12km NAM was the latest and greatest, so it's hard to blame him for being skeptical of CAMs LOL.
That model was fun. It basically showed what the weather would do if everything was as flat as a table top. That actually had some useful applications, but I see why they threw it out.