Thanks for all the feedback everyone :) :)

I've dropped the rear light source to a silvery grey colour, and stopped it casting shadows. It certainly changes the feel of the foreground doesn't it?

The suns have always been behind the cloud layer, though I had unfortunately washed away the visible cloud layer of the sun in post whilst adding the sun "halos". I've tried to tone it down a bit this time. Hopefully making the suns look a little less "fake". Still not entirely sure how to improve them, but maybe I'm trying to run before walking there ;)

Btw, the hill texture is derived from the Eroded Grante material already appearing in Bryce, and then replacing its bump map with a simple Texture created from Noise in the DTE (Stone Cliff type, MultiFractal mode).

The foreground rocks use the "Veiny Stone" texture, but with a very simple bump applied.

Thanks again for the feedback. Maybe it's time to take the next step and move onto another composition!