I have seen a few short features about different things at the parks. The types of things that run between shows or during breaks. Nothing in the last few months, but I remember a fairly recent segment that talked about how they came up with the design for the Soarin' Over California vehicles. (I know, not WDW, but still park related...)
I would definitely watch a show about the parks. They certainly have enough material now, with 6 parks in the U.S. alone.
But then again, my son and I watch the planning videos for entertainment purposes, so we might not be the average viewers...