On handguns with short (2"-to-8") barrels, a heavy barrel is really only about weight and balance. The difference in stiffness of a 6" barrel even between a light weight and a full PPC 1.25" bull is so tiny as to be meaningless.
The elimination of a barrel bushing in a 1911 type hangun can be an accuracy improvement; but a bull barrel isn't the only way to do that.