Sure, de_dust2 isn't what one would call eye-candy. Still, it uses well-matching textures, has no graphical glitches and doesn't look like something pieced together from parts that don't belong to each other. It doesn't have great design in the sense that it makes you drool... but it does have great design in the sense that it creates a rether nice atmosphere... this can't be said of many of those fun maps. Some of Nipper's stuff is nice, and I was really surprised by de_vangogh - that's an awesome idea he had there, and the result looks quite nice. Gotta check out de_cliffcastle one day...
Still, when I compare de_vangogh with de_halla, I go for de_halla.
Although I gotta admit that Nipper does have great ideas. 9_9
Anyway, I think many ppl like his maps, so having waypoints for them is always a good thing.