Medieval Door with PBR materials

That would create some nice variation in it and only improve it further. The circular shape is already reinforced by the stairs so that stays in there regardless and the change is a nice little addition.

I like the textures and design of that door, but it feels or too wide or not tall enough.

The change might be nice, but if I had to modify it I'd think about how it will look if you open the door (the stairs tile with the upper floor), just so you can reuse it in a level. If you can tile the current one it may not be worth it.