This is a pretty specific suggestion, but it's something that I can't unsee now that I've noticed it. In a lot of open grass fields and distant LODs of trees, the roughness or specular values seems to be at a weird spot. For example a whole field receives one big highlight giving it a dull, washed out look which is brighter and less saturated than it should be. I made a gif showing this when it happens to trees. You can see it switching between the the high-poly trees which look good, and the low poly trees which have the blown out look. Once you notice it really kills the immersion and isn't helping with reducing LOD pop. Whole fields end up looking like something other than grass, more like a waxy paper or something. Everything else looks amazing, though!