I don't understand this constant urge to overemphasize "providing width". Our fullbacks overlap all the time, and are ideal in freeing the wingers to cut inside while providing another free player out wide. When you think of it, the best possible combination is to have a fullback go forward on the side where the inverted winger is. For example, Villa cutting inside while Alba goes forward to stay wide. This means, however, that the opposing fullback and winger need to stay in their primary positions. Then just go between attacking through the left or right. Our best games this season came from utilizing this type of system. This is exactly what Villa is doing, and it works perfectly in Barca. Aguero (or any other forward of that type) could easily work in the same way. The team could play with no traditional wingers and just use forwards to cut in when attacking, and go out wide when not attacking, as long as they use the fullbacks the right way, and granted that the forwards have a good workrate.
Disclaimer: I'm not saying Barca needs to buy Aguero or anything like that, I'm just addressing this idea that I've been seeing very often lately about how many forwards would be useless because they're "not wingers". As long as they have the right type of movement, positioning and workrate, they can play wide for Barca. Obviously this excludes the likes of Ibrahimović or Drogba, for example, but guys like Aguero would do.