I disagree with this part of your essay: "But, why should players be expected to ... assist in its development in order to play it properly?"

This assumes that there is one "best" way, but a quick look at the many addons that do similar things shows that different players want different features and behaviors. So Blizzard delivers the core set and we get to play around (or not) finding the extras that make us wiggle like puppies. You all wiggle, right?