Hmmm. I agree with you that they take turns going forward. In fact I think that hints more at 4-5-1 as if there was one player who was a constant then Id think it was 4-2-3-1 with a more advanced player. When Derry's playing it could even be argued it's 4-1-4-1. Derry sitting and Barton and Diakite "do their thing!" Totally agree. Despite his brilliant goal he wasnt great in my opinion and Derry will definitely make us stronger defensively.
The fluidity of the formation leads to many different takes on it I think mate! From my seat in S block, Barton and Diakite played much deeper than Buzz, who played central with Mackie and Taarabt each side of him and Zamora up top..............4-2-3-1.