Ballsy but i like the idea against teams who park the bus. Gives us more options up the pitch and Dier could drop into the back four and make a 4-2-3-1 on the rare occasion the opposition do have the ball in our half haha. Would love to see it. Highly doubt it though.
By that token, why not 1xCB, 2WBs +1 DM dropping deeper when we're out of possession.
In many respects that's how we play anyway when in possession, so 3CBs against a parked bus is somewhat MORE defensive.