It's a common mistake with the kind of view : you put sometime shadow, sometimes not.
So it's seams too flat. Same for the wall and the water, stair.
I don't know why but it's really like rpgmaker tile (no offense), but you mix some tile with many textures, close to tile without any.
So this is an exemple , not very perfect but it work well imho: lot of strong shadow, good contrast too and textures for all materials

I know well , shadow is a pain in the ass but it really give some deep to your map
I suppose it's just the floor tile, because you need to add some trees and others stuff.
You know, we focus easily on little problem because lack of details.
I don't like vx tile but i need to tell this mockup isn't bad : lot of details so we can forgot the lack of some shadows