It's been a hot minute since I played GW2, but I feel like FFXIV's maps are a bit too small for flying like this, perhaps I'm misremembering though.
You also have to take into account that GW2 has a lot of verticality in at least the newer zones. Nevertheless, I'd like to see a more engaging flying than a glorified noclip with a speed modifier, but I understand that it'd need to be either restricted to specific zones made for it, or with some sort of zone reworks.