@noodlehair @Pogue Mahone -
The advantage of it is 'theoretically' we will have numerical advantages depending on who has the ball throughout the match; we can either shut down their attack numerically or overdo their defence by numerically attacking them.
Just for example think of it like this
Bailey Rojo
Blind
Valencia matic pogba young
Martial
Lukaku rashford
CB's - playing with 3 at the back isn't playing with 3 stallwart defenders like José has us doing - it's playing 2 defenders with a midfielder who drops back in between the defence when the ball is not with us - the defence gets wider as this happens; not only just blocking a single striker like morata but also blocking the channels- basically creating a defensive wall.
Wingbacks - due to being outnumbered in the centre; the wingbacks fall back to defend the width the opposition are likely to attack. They are midfielders who drop down to defence to create a back 5.
Take this as an example of the back 5
Valencia - Bailey - Blind - Rojo - Young
We should 'theoretically' win the ball due to numbers and our first line of defenders are our wingbacks. Say for example Ashley's ypung or rojo intercept willian on the right wing; the ball needs to be played back to blind so blind can pass the ball across to Valencia who should be free on the opposite side in defence. This should be the main tactic of our counterattacking play; to find the free space to attack.
That's what happens in defence - 2 wide midfielders and 1 defensive midfielder drop down to protect our main 2 CB's - (the CB's we would play in any formation). It's these same midfielders who push the ball on from the back to initiate the counterattack.
Valencia or young join the forwards; the same way they joined the defences on the wings - since we have the protection of our main 2 defenders with a player like Blind; they do not need the protection of the wingbacks.
Just as much as blind would drop down to defend giving us 3 at the back; we would have a support striker who joins the forward on the attack & drops down on the defence. Say for example martial joins the attack.
Valencia Lukaku Martial Rashford young
If we lose the ball - Martial & the wingbacks all drop back again to outnumber the opposite team on the defence and on the attack.
There needs to be a player who drops in to defense as much as there is a player who joins the strikers - it allows us to switch from a 532 in defence to 235 in attack; without us being at risk of being hit on the counter attack.
Its a mix of possession & counterattacking; José has us at 532 consistently because no one can initiate the attack.