The beef is that there are many millions of words of unpublished Realmslore about the core Realms (which Jeff Grubb called the Heartlands, and is both the most popular and the most fundamental to the setting), and that the last 'detailed' sources on them, the Volo's Guides (which never covered Sembia or the Dragon Coast), only skim the surface of that material, lack detailed historical or political information because of the focus of their coverage, were published more than a decade ago and are only available to the minority aware of the online downloads (as well as the fact that, I think unfortunately, the current timeline is 8–17 years ahead). There is easily enough material for ten 160-page books each on the Dales, Cormyr, the Western Heartlands, etc., and while I love adventures (and they're essential to the health of RPG lines, even when their individual sales are low) and seeing the outlying regions detailed too, Wizards has published no Heartlands regional sourcebooks at all in the six years of 3E.