http://soccernet.espn.go.com/blog/_/name/tacticsandanalysis/id/5?cc=3436
Now I'm sure this has been posted on the forum already, but it's a fascinating slant on the Van Persie signing and how that related to Kagawa. It's written by Michael Cox, the brains behind ZonalMarking.com, and was posted before the Everton game, from which the early signs seem to support this tactical theory.
Basically he suggests Fergie is looking to create something of a 4-2-1-3 with Kagawa floating behind three interchangeable forwards, similar to what we had in 08 with Rooney - Ronaldo - Tevez and what Jose's Inter had in Eto'o - Milito - Pandev. It certainly explains the pursuit of Sneijder (as a playmaker) and Hazard (as a wide forward), but raises interesting questions about Valencia - his complete lack of versatility means he can't really be a wide forward, but he is our player of the year and shunting him either out of the team or to right back, as against Everton, seems ridiculous.
Having said that, some combination of Rooney, Van Persie, Nani and Welbeck, with Hernandez and Young to offer something different from the bench, sounds absolutely lethal. Definitely fits the bill in terms of interchangeability, with a constant supply from Kagawa in behind.
Could well be pure speculation but interesting nonetheless.