I'm siding with the dubbing as a historical quirk crowd. If anything, the fact that fish take dubbed flys, and also a lot of underwater debris as 'food' is proof that they aren't very selective AS FAR AS REALISTIC IMMITATION is concerned.

Sawyer tied his Killer Bug with wool yarn and it seems to catch a fair number of fish, but less than the number of tyers who get caught by that wool yarn Let's not forget his PTN as well.

And as far as my personal choice, its smooth bodied patterns by a mile. I do tie GRHE's but after 5 fish or so the spiky/buggy dubbing is worn away and it becomes unbuggy. That's when it gets good and catches 10 or more fish