One factor that you guys ^^^^ are neglecting is the role of protein in satiety.
Some people (myself unfortunately not included) find that protein blunts hunger more than do the other two macros. For those people, an "excess" of protein may be preferable to extra quantities of the other two -- even if the extra protein doesn't ultimately contribute to muscle building/repair past a certain point -- simply because it serves as a safeguard against overeating.
There are also some studies on the efficiency with which the body uses calories of the different macros. I don't remember everything exactly (I will look them up again when I have more time), but some studies purport to show that the body only avails itself of 0.7-0.8 calorie of actual food energy per 1 calorie of protein consumed. By contrast, those studies say, the body is very efficient at using (and not wasting) the whole 1 calorie of carbohydrate and/or fat.
This totally looked like junk science to me when I read it, but it's borne out by my food diary. Specifically, when I go back to Uruguay, I eat absurd amounts of protein (sometimes north of 400 grams on workout days) and a lot less carbohydrate. And sure enough, according to the diary, I can consume an extra 300-350 cal/day (= about 20% of those protein calories) and still be at long-term maintenance.
So, even if protein doesn't particularly blunt your appetite, you may come out ahead of the curve by eating more of it, even on an isocaloric diet.
Of course, anecdotes are not data, and so YMMV.
And for you lucky bastards (aka "hardgainers") who don't have to worry about keeping your appetites in check, well, you may want to do the opposite. Proportionally less protein, more carbs and fats.