AnotherGuy
Hero
Yes, but the Gazetteer predominantly created content for each new area explored.Please do not interpret this is telling you you can't have your own opinions, but I do want to raise a point.
Mystara was the line that rewrote magic users to get name-level followers when a new kingdom's Gazetteer came out, created new (race-as-) classes never previously playable creature types (and no few new to the world) with each Creature Catalogue entry, and added colonies of winged minotaurs whenever the Princess Ark made another port call to fill Dragon magazine pages.
I'm also a huge Mystara fan, but IMO, it's a perfect example of a setting that rebuilt itself for every release.
Suddenly dumping several races in the Emirates, the Principalities or the Northern Reaches would alter those settings.