As great as Lee Wulff was, he did not know how to tie full dressed feather wing salmon flies, perhaps that is why he had no use for the "fancy feathers". I had the great priviledge of meeting him and seeing him tie a #12 Grey Wulff in his fingers (no vise and no bobbin) while standing up at a FFF Flyfishing Clave in 1981 in West Yellowstone. Lee was a gentleman and a very knowledgeable fisherman; however, he was not a great flytyer, although he tied flies that worked and worked very well. If it were not for Dan Bailey and his tyers, Wulff's flies would not have developed the following they have.
Yes, simple grey, black, brown, olive, and tan nymphs tied with a sparse tail, wool or herl body, without wing cases and having a turn or two of soft, mottled hackle at the head are very efffective indeed. For the large stoneflies, flies tied the way Charlie Brooks (who I also has the pleasure of meeting and getting to know) that are tied in the round with wool or yarn bodies, split goose or turkey biot tails (or rubber legs material tails), and a grizzly hackle dyed brown or tan along with a natural grizzly hackle tied over the thorax of the fly (right over the yarn or wool) and with a white or very light grey ostrich fiber that are all wrapped just two wraps over the thorax with a slight space between the two wraps is most effectie as well.
Eastern helgramites tied like Bob Clouser's Helgramite, black or very dark slate grey ostrich fibers (about 15 or 20 of them) tied like the marabou tail of a woolly bugger and clipped off a full shank length beyong the hook, a black chenile body, black or very dark slate grey saddle hackle palmered woolly bugger style, and black rubber antennae is a superb fly for smallmouths.
And small (#8 to 12) steelhead or salmon spiders tied low water style with no tails; a bright little (and I mean little, only one turn of material) butt of florescent braided mylar, yarn or floss; body of black, purple, dark blue, or claret, dubbing; and a sparse oversized hackle in black, claret, or purple is a superb fly for the skinny water of late summer or early fall.