I think people familiar with how great HW zones feel with flying enabled might not remember what a pain in the ass the zones were when first approaching them on foot. Everything was so much larger and wider, there is a bunch of verticality, but it was a mess to traverse. It was slowass, and doing simple quests which required you to explore certain areas or go back and forth were a pain in the ass.
Coerthas Western Highlands is a beautifully conceived zone which was a terrible experience when I had to get through it for the story. Once you unlock flying on it, you really get to appreciate how great it looks from the air when looking down, but on foot it is dreadful.
I liked the Dravanian Forelands both on foot and with flying. Probably the best designed HW zone in terms of gameplay balance, and it had rad optional vistas.
The Churning Mists and Sea of Clouds were also zones designed for flying instead of ground travel. Churning Mists in particular was super annoying to move around in on foot. Sea of Clouds gets much better in the second half when you return to it. Both are very pretty in terms of art and the idea of flying islands is great, but it just wasn't that fun to actually PLAY through.
Dravanian Hitherlands is boring af. Worst zone in HW imo. Both on foot and in the air, it's just boring shit over and over. Lame ruins, shit that get in the way of you moving or looking for quest objectives, lack of color, lack of interesting enemies. Not good.
Azys Lla was a fantastic endgame zone and had great art direction, great enemies, interesting components, the flagship is an OMG moment when you fly towards it.
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In comparison, so far I think the Stormblood zones have been very well designed to be fun to approach on foot first and foremost. There are already areas I'm excited to check out once I unlock flying in each zone, but there's a much more grounded feeling when exploring where you don't feel that it's annoying to navigate without being able to move vertically.
Fringes has a nice mix of forest and desert, leading to a great view of the bridge. Peaks has a crazy ziggurat thing, but might be the most boring SB zone so far. Maybe there are more interesting bits later, idk.
Rhalgr's Reach is a fantastic small scale safe zone and I think it has more attention to detail in the art direction than Iydllshire. Kugane >>>>>>>>>>>>>>> Ishgard, no questions. PS3 died for that scale.
The Ruby Sea is an evolution of a wide open water/beach FFXII zone and there's literally nothing like it in all of XIV so far.
That's about as far as I am now, but yeah, I wouldn't say HW > SB when it comes to zones, especially when we take gameplay into consideration.