Since I dont want to spam in the comment section I thought I open a discussion.
Except for the seemingly low res cliff texture a have noticed something else: the color of the sand texture. Of course the choice of color kind of depends on your taste and for me it is too red. But I think the valid point is, that it is somehow unrealistic. Look at the color of the cliffs/mountains. During spring the meltwater from the mountains caries a lot of rocks, pebbles and stuff downsteam which stop somewhere in the river. So this gravel/sand texture should have approximately the same color as the cliff texture. ;)
Btw, this goes for European and Boreal, too. Tropical was ok I think.