It's not really to do with the players for me - we might miss Pogba, but no great team stops being able to play because of one injury. We've plenty of players capable of passing and moving, it's just that they don't.
It's surely to do with Mourinho and his setups/methods. Conceding possession and worrying more about not losing than winning is always going to lead to failure, or at least a weaker mentality. City aren't that much better, I just think they believe they are. They must go out every week, against Palace or Madrid, and expect to win playing their own game. That breeds confidence, and that's how winning teams are created. That's where composure comes from - believing in your own and your teams ability to thread a pass, take a risk, keep possession.
We might win something (as we did last year of course) playing tight, compact football with a couple of superstar players making the difference, but we'll always be much more at the mercy of injuries and suspensions, and we'll have to hope that in games like the one against City, the opposition aren't firing on all cylinders. An attacking, proactive, possession focused team on an off day struggle to score, a defensive, reactive, counter-attacking team on an off day struggle to stop the opposition scoring!