I think Norm's genius was his ability to simulate details in a limited space. He knew the images were going to be reduced so he added a kind of loose detail. It isn't fussy or tight at all. Once the image is reduced, it all falls into place and look rather amazing.
I also think copying a Saunders character is one thing and it's another thing to be able to apply his style to someone's own work. For instance, Plan 9's ability to paint the Kleenaxe guy was stunning. I don't think, however, that the Sweet 'N Slow woman looks like a Saunders piece. I think it's bold thing for a painter to attempt to replicate his style but still difficult to accomplish.
Glad you bring it up. If the word "difficult" scares any artist then he should get out of the business. The difficulty of great art is making it look easy.
I've seen artists and even non-artists replicate cartoon styles with their own flair. It can also be done with paint. I don't care if the work doesn't look exactly like Saunders, as long as it's good character illustration. If we all took a Norm Saunders course we would learn valuable information but apply it in our own ways.
It's not fair to compare my progress from my Kleenaxe character to Sweet n Slow. Sweet n Slow was severely rushed. Secondly, nobody is going to progress much from painting number 1 to painting number 6. I'm going to be hit and miss until I've had a lot more practice. I just hope I can find the time. I'd like to create the next Mars Attacks-type card series one day.