The way tessellation works will always not be as good as real 3D geometry. You can control the degree of bumpiness but you reach a point of dramatically diminishing returns very quickly when you add too much bumpiness, it starts to look like a Martian landscape and very artificial.

The quality of tessellation in FFXIV is limited by the relatively low resolution of the textures, since tessellation is adding parallax based on the actual texture and the higher resolution the textures, the more parallax can be added and the better it looks.

Considering what is being tessellated in this game, that's pretty much as good as it can look.