Ken McKown writes: They say war doesn’t change. In the case of Call of Duty it rarely does. The franchise has seen its ups and downs over time, but last year’s Ghosts was especially disappointing. A lot of people thought it was finally the beginning of the end for Activision’s juggernaut. Then Advanced Warfare came along; reinvigorating what makes the series so popular, while also changing the dynamic of its most popular feature: multiplayer. Sledgehammer has breathed new life into the series. This is a change for the better. The only problem that could stem from this is I don’t think I could go back to the old style of Call of Duty after experiencing Advanced Warfare.