I know there is a way to project the textures always in direction of the normals. That would help your terrain a lot. Maybe we can find out how that works.

All in all I like the scene. but the texture for the grass does not fit to the texture of the grass models. So I think that causes that look.But if you change that and the issue with the terrain it will turn out really good.

PS: did you got it to get the shadowmapping work property?