Some background info may be helpful in forming an opinion. Here are two articles on Pope & Young. (No, they weren' t two guy who started a record book, but popularized and legitimized bowhunting in the early part of last century.)

http://www.stickbow.com/FEATURES/HISTORY/DrPope.CFM

http://www.stickbow.com/FEATURES/HISTORY/ArtYoung.CFM

Glenn St. Charles followed suit in the middle part of the century, legitimizing the bow as a viable hunting tool via the Pope & Young organization. Here is a link to an interview with Glenn (now in his 80' s I believe), which includes (in part) his thoughts on continuing technological advancements. The media clips take a while to load, but he gets his point across particulary in clips 3, 9, & 10.

http://www.bowsite.com/bowsite/features/interviews/stcharles/

The Pope & Young club today has mearly drawn a line in the sand as to how far they are willing to accept technology. If not at 65% letoff, then where? 80%? 90%? 100%? 400fps? 500fps? At what point is modern equipment no longer recognizable as bows?