Yes, yes, we are only at patch 4.1 with most of Stormblood way ahead of us. But it is never too early to talk about what you want to see in the future. Besides chances are the zones for 5.0 are already in the work, or will soon be.
Soooo the question:
What kind of zones you would like to see? We had deserts, forests, steppes, floating islands, floating sci-fi islands, large steppes, and rice field filled valleys. And we had the Sylphlands, AKA and LSD trip. We also took a trip underwater with half of the Ruby Sea.
So what landscape would you like to explore in the future?
One I wouldn't mind seeing is a city. Not like Ishgard or Kugane, but an open world zone. A mostly hostile urbanized setting.
Wish number two would be a swamp. A gloomy, mist filled dangerous, monster infensted, horrorfilm kind of swamp.
Maybe the inside of a giant creature. We had a battle on Bahamut's hand. How about going inside something giant for a change. Like the Wandering isles in WoW except inside, not on the outer shell (this could also be a dungeon).