It might be interesting to have a world map where all the available sceneries are displayed on their in-simulator location with a dot. Clicking the dot would bring you to the store page of the scenery. Orbx Central and the Contrail shop application have this feature, labelled as ‘Discover’. Which looks like this:
This would of course be more work to implement compared to a simple regional filter, but it would allow users to more easily find the sceneries in the locations where they want them!