OK - I ran a few more missions to try to compare stock versus Fubar's in terms of two key aspects - NML and the horizon haze. The two screenshots show basically the same part of the terrain at about the same altitude, time of day etc (re-flew the same career mission):
First, stock (except for the Battlesmoke mod, which was on for both these tests):
Then Fubar's latest (again, with Battlesmoke mod on):
First, I like how the horizon is straighter with Fubar's mod than with stock
Seriously, in general I do like the way Fubar's textures look on the normal terrain, compared to stock. I also kinda like the way the trenches are toned down and don't stick out like black zippers quite as much with Fubar's mod. And I also like how NML itself isn't a totally-obliterated, featureless morass and that some of the underlying topography/lines, etc. show through with Fubar's. (I went to look at some WWI aerial photos, and many did show some hints of the underlying patterns surviving a bit). However, I do get the sense that maybe a little too much of the underlying textures (furrows, pathways or whatever) is still visible with Fubar's, and the trenches are just a bit too indistinguishable as a result. I think it would be great if there's a way to have it somewhere between the two - a little more obliterated than Fubar's but not as much as stock.
As for the horizon - I do like the sense of being able to see farther with Fubar's but I'm wondering if maybe it's just a little too clear? I'm struggling a little to reconcile (in my mind's eye) the seemingly total lack of haze over the land "below" (closer than) the horizon line with the band of white haze-like color in the sky above the horizon line. The white band seems about the same in both, but the contrast due to lack of haze in Fubar's makes it look a little odd to me. Again, I wonder if maybe somewhere in between - just a little more haze than Fubar's but not as much as stock - would be better. I'm not sure if there's any way to tone down the white band in the sky and keep the look of the land (or close to it), but it might be interesting to try.
But all of this seems fairly nit-picky, as overall I think Fubar's mod is very impressive so far.