I would have to say that the more motion the better, at least I think so. However, I used to always have trouble with the tail wrapping itself around the hook bend until I read that A.K. Best recommends tying a few short, stiff guard hair fibers (like a small tail) before you tie in the longer marabou for the tail. It keeps the marabou away from the bend and it certainly doesn't seem to bother the fish catching qualities at all.
If I wasn't always confused, I'd be worried.
Joe