I agree. An informative documentary like that would be not only interesting (especially to new developers), but such works would also serve to educate the general public about the importance of indie games.
For instance: Even among "hard-core" gamers many don't see the appeal of indie games, and they may still only play AAA games after seeing such a documentary; However, next time they enjoy a "new" game mechanic in their mainstream game they may wonder what game first explored the mechanic -- Chances are it was an indie game.
After many years of him mocking less polished indie games my cousin was finally cured of his philistine ways. He now appreciates games other than just flashy & expensive AAA games after I explained to him that mechanics in the Portal game(s) he loved was the result of experimental indie game devs, and that this sort of thing happens all the time. That small crack opened him up to the idea that less massive games are worth a look into, thus he's now frequently telling his friends about some new indie game they've got to try. He has a much more varied appetite of games now and a greater appreciation of the art of game making -- They're not just gimmicky toys or "just interactive 3D murder movies" to him anymore (his words not mine), and he now sees the point of protecting game developers' right to express themselves in games. So do many of his friends now too.
It's hard for some folks to extract much value from Indie Game The Movie if they don't already care about the games the movie revolved around...
A wider ranging documentary that covered the points you've mentioned would be a great source of information to point folks to. I think it'd be a great benefit to indie game developers and game players alike.