I'm not suggesting we should use that every time, the best teams are always making alterations and adaptations to formations to make sure they are always organised. We occasionally change our formation, sometimes it works and sometimes it doesn't but that's the way it goes. Rooney would have some freedom, there's that entire space behind him for him to operate in. The trouble is as you say managing to give so many players game time. There are very good players such as hernandez, welbeck, anderson, carrick etc on the bench. But the truth is we do need to evolve. We should be competing for the champions league and to do this we need to make big changes and take chances, we're not really going anywhere atm, I mean we're the biggest football club in the world after all.
Anyway it shouldn't be too condensed, I deliberately left a space between rooney and the cm's for the am's to utilise if need be, had I put a cam there then it would certainly have been condensed, but I'm hoping there's some space there. If you mean the bit with martinez, pogba and clev is condensed well bear in mind they're not fixed in position during the match, the likelihood is one of them could drive forward.
I've just noticed as you say it's similar to barca's formation, I know we want to continue our way of playing, but that is a good indication it'd work! And for the record inzaghi WAS wc.