Very good article!

Even so, we will all wonder how penetration is affected by live, lubricated flesh when using a razor sharp broadhead.

It is my gut feeling that, sharpness of the broadhead may play the major role in penetration through live flesh. There may be little or no friction created by the shaft and the key may be reducing friction on the broadhead. This would be best accomplished by having fewer blades and sharper ones, along with a cut-to-tip style.

It seems to me that this kinetic energy stuff is most important, only when you miss. The very best advise may be to spend less time worrying about the weight of your arrow and more time making sure you can hit what you're aiming at and to use only the very sharpest of broadheads.