There was a line cut out where they get into the Death Star and Wedge sees the big reactor thing and says the x wing torpedoes won't even hurt it. But the Falcon and its tricked out gunnery can. In essence it would not have worked if the unconventional Falcon hadn't been there. If that line had been left in it might have alleviated the idea that the same mistake had been made twice. (And made good use of the "character" of the Falcon as well and adding weight to Han's insistence on it being used.