You can kill gobblers with a 2 3/4" trap load if you shoot them in the head, and 2 3/4" Magnums will kick the snot out of the Terminator and also kill anything that Gobbles.
The only reason for the 3.0" or 3.5" Magnums existence is steel shot capacity for waterfowl.
Definately NOT needed for any upland hunting, including pheasants in the corn stubble at 50+ yards.
I'd take a light short 2 3/4" upland gun any day over any and all 3.0" or 3.5" guns.
The added speed on target will more then make up for any perceived range increase.