I actually like the green look on this and imo you are in the right track.
CC:
* The tower needs some shading, specially inside it. You can do that with the "render to texture" technique, just make sure the light source in your modelling program matches the sky (duur)
* The roof edge looks too simple and weird, hope those wood supports are just placeholders.
* Decals are needed in some places to break the repetitiviness. (specially next to the arches)
Hope that's helpful!