Dier and Vertonghen are both big, footballing and mobile centre halves, which is the only way you can make this work. Maybe there's an argument to play Vlad the Impaler in the middle of them - but he's apt to brain fart. My logic was that if Fazio can dominate aerial duels then the two more natural ball players either side would make the thing work.I have yet to see a team successfully play a 3 defender formation in the prem. Mancini tried it with city, Rodgers tried with pool, redknapp with qpr, van Gaal with united and so far they have all failed. Poch doesn't favor it, it's just not gonna happen.
I left Stromboli out as I've never seen him play
I left Rose out because of his defensive frailties, but he is effective going forward, so might warrant inclusion in some games.
IMV its not the formation that's a problem, its trying to shoehorn the wrong players into it that makes it a liability.
If you have the right players - or just a lot of excellent players then the formation is pretty irrelevant - as long as everyone plays to it.