I think the knife bounce needs SERIOUS tweaking. If you miss a flip throw (which happens to me a lot on insane) then the knife bounces back in an almost arbitrary direction every time. Throw it against a rock and it almost flies back at you.
Will this be fixed in L2? Does any one other than me hope for this?
Knife Bounce

These are the images for Complex Rigid Body Dynamics, back in January 2006.
Oh yeah, it's before the blog (though everything is in the blog now).
http://wolfire.com/forum/viewtopic.php?t=911