Glad to hear that Arie's doing well since his injury, Spirithorse!
As far as the clipping goes, I only clip the bridle path if I'm not showing, sometimes excess feathering if it starts to collect snowballs or mud too badly. If I do show (something that happens less and less these days... I think I'm becoming disillusioned with competition, lol) I do a full trim: Feathers, beard, whiskers, and the fold-and-clip-what-sticks-out method on ears. I don't notice anything different about the behavior of my guy whisker-less vs. whisker-bearing, but as a matter of general grooming I do let them grow. My sister's QH, on the other hand... well, his whole head could be one giant whisker and he'd probably still be a klutz with his head and face.