One thing I think is important for gameplay oriented world building is to not hinge the world on a singular story within it. To use Eberron as an example again, the nature of the Mourning is indeed an important and interesting story in the world that can fuel all kinds of adventures, but even if a campaign solves the mystery or even undoes the Mourning, Eberron as a world continues on. The world changes,which is good, but the next campaign can follow in the same Eberron.
Worlds built around a singular, defining central story -- Krynn for example -- are often less easily adapted to other stories. This isn't always true, of course, but it is telling that Krynn got a lot bigger as 2E wore on, in order to try and make it a broader world with stories to tell beyond the War of the Lance and its fallout.
Worlds built around a singular, defining central story -- Krynn for example -- are often less easily adapted to other stories. This isn't always true, of course, but it is telling that Krynn got a lot bigger as 2E wore on, in order to try and make it a broader world with stories to tell beyond the War of the Lance and its fallout.