Found some neat ruin scans randomly and really wanted to do something fun with it.
Beautiful! Maybe a tad to green all in all. You could make the ground (except the grass of course) a little less green and maybe place some plants on top of the walls to cover the photogrammetry vegetation there.
Great scene, and very nice ruins. Hannes is right; pop some ferns and grasses, or even small shrub on the ruin. I would also add a small scale (0.05-1-0.01, mix 2 or billows) fractal though transform shader set to world to the default shader, as bump in the stones of the front ruin. Especially the entrance big stones are a bit too smooth, IMO.