I suspect that what you are seeing is just one of the characteristics of te 24fps.
The simple fact is, that 24fps footage motion looks nothing like (some would say "blurry") the 60i video footage people are used to seeing, where motion is much smoother.
You could shoot with the cheapest palmcorder at 24fps, or your mid-priced XHA1, or real film with a million-dollar Panavision camera... the motion characteristics are still going to look the same.
If you really watch for it, it's amazing how "blurry" fast motion (or even moderate motion) can appear in even zillion-dollar Hollywood feature films.
Sometimes that's unavoidable, sometimes it's even desirable, depending on the aesthetic look you're wanting for the shot.
There are tables that list "do not exceed" rates for pans and other camera movements (based on frame rate, focal length, and format size) in the ASC manual... but I don't know anyone who actually uses them. It's pretty much a matter of practice... most shooters know how fast they can move to retain sharpness... and in which instances it does or does not matter.
I don't think it has anything to do with the HDV GOP since you described it as "blurry." If the GOP was the problem, I think most people would describe that problem as "blocky."
Fantastic Plastic Entertainment, Inc. fantasticplastic.com