Re: 4213?
José Mourinho - Pretty sure that's the guy who came up with this. Pretty sure his first stint at Chelsea with Drogba down the middle with Robben,Duff,Cole, SWP would play either side of him making the front 3. Lampard in behind and so on with Essien and co CM.
Again he used this at Inter Milan.
Current Chelsea as you mentioned. - But again it can different in and out of possession. You need fit and disciplined players to make it work.
It's real its been used. It can be counter attacked. - It is still dependant on player roles and how attacking (adventures one wants to be)
Every formation has pros and c0ns Depends on what players you have and what truly works with them.
It's like the 4-2-4 - It's unconventional but you see it in action. As long as the 2 outer wingers are disciplined enough to work back to a more 4-4-2 out of possession you then turn back to 4-2-4 with possession.
Ultimately every formation has strengths and weaknesses. The issue most of the time is dragging players out of position and leaving yourself exposed. That can be the real issue.
Just my take on it.
