As a player of only GW2 and not GW1, I can’t give you a good explanation. But I only recently have I found out about Cantha and Elona, and their culture insipired environments.
I do hope that someday Arena.Net may expand their living world that would create even more diversity in the environmental aspects of the game.
I think that this would also expand rather diminish the player-base as it makes the world feel larger and more alive when there are Eastern and Western inspired environments; there’s more areas the explore to the player’s liking.