There should be balance in everything. Some go Heavy, heavy and won't shoot anything else.
Others shoot arrows extremely light and some even below IBO minimum weight. Not Good!!
I personally feel something in the middle gives you the best of both worlds. I prefer to shoot somewhere around 6 to 7 grains per pound, with a minimum FOC of at least 12%.A well tuned arrow at those specs will have more than adequate penetrating power for anything on North America.
Dan