I still say KSY has a "Film School 101" look and feel to it, but in a good way. It's not overly stylized, and it doesn't rely too heavily on a lot of special or visual effects to carry the movie... and of course, more of actual puppetry techniques were utilized, as opposed to the heavy use of greenscreen and chromakey that both Disney and SST seem to always rely on anymore these days (even though KSY does have it's fair share of occasional such use). In short, it almost seems like either a student film that took a lot of time, effort, dedication, people to make, or a Sundance-esque indie film that actually had a pretty decent budget. As a teen, watching it made me feel like the kind of movie I could make myself.
Really, my only minor quibble with KSY is the inconsistency with the time period: it's clearly supposed to be the early 50s if it took place around the time Jim was in his teens, yet a lot of Croaker's slang and terminology, as well as George Washington High School are too modern and anachronistic to work.