I like the weathering on the ruined stones. They (the stones) could benefit from a little variation in colour, just subtle variations would be enough to kill the "primed black, drybrushed grey" look. You could also add some little bushes or dried branches scattered around the floor to add a little bit more of variety to the grass.
The Dragon is pretty good but I think you would win more points and votes if you more contrast to it because now is almost red and washed thoroughly with brown.
I meant to be respectful with your work, I know this is a huge thing to work on and I just wanted to help you out with my comments and critiques.
Also as this is a big diorama, you could add some more pictures from different sides and/or detailed closeups from different parts of it for the people to better appreciate your work.
Keep on painting and posting please! ;)
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