This is definitely a beautiful image! The detail in the foreground, especially on the right, with the debris, algae (or small plant growth), etc. is fantastic. The river itself is highly realistic, while the terrain is nicely understated and likewise very realistic. A great sense of natural scale and distance.
That being said, I have a few notes of feedback.
First, the clouds are nice, but I swear I've seen something quite like them before:
https://www.artstation.com/artwork/9ryEvProbably nobody else who isn't a close follower of your work would notice though. I'm just a big fan.
And you've done some other great cloud shapes before, so I'd love to see another new cloudscape from you. Or maybe just hit random seed on these guys.
Second, the colors for all the vegetation are great, except I think for the largest trees. They seem to have a bit too much blue and/or saturation in their color to my eye. The model also seems to have leaves kind of oddly scattered around, though this may be realistic for that tree type. They just look a bit like a more simplistic point cloud tree generator might make, rather than a growth-based model or a well-informed hand-made model. I also think the specular might be just a little too high on the leaves. Overall they just stand out as a bit less realistic than every other part of the scene. They're not bad on their own, just everything else is great.
I also wonder what this would look like path traced, not so much for the vegetation or landscape, but for the reflection on the water. Path tracing enables a new specular reflection model that I think looks rather nicer. But you might have to adjust settings if you enabled it as the new specular model works differently and the reflection might be too soft for your taste (this can easily be adjusted, just in a different way than you're used to (Minimum Highlight Spread in the Water Shader's Reflection tab, very small values, with a 0 for sharp reflections).
Finally, like many of your images, I find this to overall have a rather "dim" and yellow/orange cast to it. It's not quite like a sunset (which I tend to like), but maybe late afternoon, with a very heavy and humid, dense atmosphere. I often think of these oppressive and dramatic weather days in the South-West of the US when I see your images, and this one is similar. It's not a bad thing, but aesthetically not my personal preference. I did a little quick adjustment on my side here and with some minor adjustment in white balance and exposure I liked the image even more, and could appreciate it more as a beautiful view and not more primarily as a great technical achievement. Again this is no doubt personal taste. Which is why I put this last.
I'm happy to post my quick edit if you're curious what I mean, but I don't want to detract from discussion of your work, so I've defaulted to not.
In general always glad to see your work, it's always up to a very high standard of quality, detail, and realism.
- Oshyan