Actually,people have been arguing about light arrows versus heavy arrows for a very long time.I was reading the 1943 Ye Sylvan Archer recently and they were talking about the light arrow,heavy arrow controversy the.In that issue was the article by Fred Bear where he tested 6 different bows with 300,400,500,600,700 and 800 gr arrows.In every case,the heavier arrow out-impacted the ones lighter.Fred made a point of saying that the 61# bow with a 500 gr arrow only out-impacted the 45# with a 600 gr arrow by 1%.
He also made a point of saying that there needed to be a balance between arrow weight for penetration and trajectory for being able to hit game at longer ranges,mentioning out to 40 yds.Those were self bow days.People took a lot longer shots at game in those days than most today would think is ethical.
Fred chose 10 grs per pound as the ideal balance between penetration and trajectory.Keep in mind,later,with laminated bows,Fred Bear took shots on game out to 100 yds.
If they were disagreeing then about light arrow,heavy arrow in 1943,and we are still talking about it 68 years later-there will never be a consensus.
Use the combination of arrow weight and speed that suits you and have fun.Probably the majority of bowhunters are shooting small to moderate sized whitetails and most setups with a tuned arrow and sharp broadhead will work fine,so it is a non-issue.Some will hunt bigger,tougher game but I have a feeling common sense will prevail most of the time.