The original canyon had some texture to the miniature and walls which gave it a good sense of scale. The revisited canyon looks to only have one size of texture on it, and it's so big relative to the ships it no longer looks convincing.
I'm also a long time lurker who generally loves what you do Adywan, Thank you.
But I feel compelled to add to the sentiment above, I really think the new canyon walls are a step backwards. I appreciate you've spent time and effort to get it right but I think they look too modellish and as Synnove suggested it is the texturing that lets it down.
I'm not sure how to fix it, perhaps attacking it with some rough sandpaper in bits or something else to age/weather the sharp cuts on the rocks.
Anyway, it's your baby and I completely understand if you ignore this and I mean no offence to your amazing work.