It will still stretch the middle of the defence wide open for midfielders to burst through. I'm not criticising the tactic (If I am then it's not intentional, your tactics are some of the best available) but surely the middle centre back would get stretched to no end. All needs done to counter a tactic such as that is to defend deep and very narrow and play counter attacking football.
Wait... Does the DM drop into defence when one of the CB's covers to close down a winger?? In which case there shouldn't be a problem