I see your point HeBeGeeBee.
I've always felt that feathers didn't effectively tickle certain body parts. They were seen more as symbols of tickling. I really don't feel that they work very well on feet, or ribs, or sides. (Unless you are using the quill).
HOWEVER, when the fluffy end is used in stategic spots, it can be very bad. The aforementioned armpits, nipples, face (if really just want to give an annoying, cruel tickle) and the bits and pieces, if you follow.
Rasputin