Mourinho has always said the most important time in a match is the turnover of possession. That transition is when teams are out of shape so defences at their most vulnerable. its the one area of our game that suffers badly as we are incredibly slow to make the transition - our first priority appears to be "secure the ball and keep possession", as opposed to taking advantage of the situation and driving forward. It is mostly because we do not have the personnel who naturally like to run forward with the ball. Silva's instinct is to pass. Barry is not a runner. Yaya can run but only a few times a game. Nasri is a baller. Milner can run but lacks the intelligence/end product to make the most of those situations. Look at how refreshing it has been to have Rodwell in recent games pick the ball up in the middle and just run into the space. Or even without the ball - there was a moment against Wigan last week where I think Tevez had it out wide and Rowell drove forward to get into the box. It puts defenders on the back foot and creates space for others.
Its something that a striker doesn't resolve, as the earlier poster stated. But at the same time it doesn't just mean a winger either. We simply need a bit of variation in play - the ability to be direct (not long ball), by getting the ball into the danger zone as quickly as possible in those transition periods. Our MO is to keep the ball, which lets the opposition recover and get into formation. And you aren't going to get the goals the likes of Aguero and Tevez are quite capable of scoring if they have 9 players in front of them.