Not really. Remember that scene at the end of Assassin's Creed 2, taking out a squad of templars with nothing but your hands and a hidden blade? I'm picturing more of that if it were to jump into the modern world for the next game. Just because guns exist in the world, doesn't mean they have to be the focus of the gameplay, the only weapon available. In fact, the levels would likely be designed a bit more so you have to use stealth more to avoid those enemies with guns, if there are any.