Well, with heavier draw weights you often buy better penetration with marginal heads, however, I really agree with a recent article I read, in fact, I have been stating these facts myself for years to those who want to listen.
Deer are fed upon by everything that can catch them. To get away, they run. . fast.
When they are hit with an arrow, if they are not hit in a bone (no heavy trauma) and are hit with a very sharp broadhead ( again the trauma thing), I believe they tend to not react as violently. They tend to stay put, or to run just a bit and then stop to see what might be out there. They don't go as far and are easier to find.
If a bone is hit, if a dull broadhead has to push very hard just to penetrate the skin, much less the rest, there is heavy trauma and the deer lights out, getting out of Dodge. They go farther and they are then harder to find.
More than just the penetration aspect, I myself think that a sharp broadhead and a good hit also helps us recover deer with less problems.
ChuckC