I agree that 1g to 1.5g is enough for most people to grow, but if they were capable of 2-3g per lb of mass, I'd certainly encourage it. 2g is better than 1g, but 1g is good for slow growth nonetheless. However, I also reserve a special place for carbs since they are the preferred energy source for muscle contractions and high-intensity activity. I just cant believe that this board still holds strongly to their high fat diets - that is so 1970's bodybuilding.
At Texas, ur last paragraph I believe is referring to an insulin-glucagon axis. The ratio of protein to carbs affects this hormone balance, which is the main factor in body composition. The other factors are fat intake and activity, of course.