If your draw length is greater than 27"..... I see no need for using a 70# compound bow for anything short of true BIG game (elk and the bigger bears).

Modern archery tackle is more than capable of excessive speeds with good hunting weighted arrows.... example... I'm pulling 63#s at 29.5" draw and shooting a 450 grain arrow right at 280 fps. That be a heck of a lot more energy and momentum than I need to shoot the German Sheppard sized deer that inhabit south east Virginia.