No, i said that after saying numerous times that you give up a man in midfield and pass the initiative on to the opposition. Resulting in less possesion and pressing. Which in the long run is more damaging.
I've played as a permanent sweeper (PS as of now) in a back four for 2 years, and it has non of those disadvantages you talk about.
A PS can choose to play at the back of the defence, with the CB and DM as a "true" libero pairing/double pivot in front of him (DM slightly more forward, and goes further forward more than the CB), or he can move up in one line with the other three defenders and the DM moves further forward (mostly for the offside trap, if desired).
It's like a mix of many formations, but defensively: a 3-4-3 and 1-4-2-3 (both with double pivot), a 1-3-3-3 and finally the common 4-3-3. The advantage is that you don't need another midfielder for the double pivot.
When the fullback moves forward, the PS covers for him until he's back. It's better that one fullback stays behind to form a 3 man defence line. He could even stay alone at the back during attacking corners, but it's not necessary, and he can also move to the left or to the right, depending on where the ball is, to balance out the defence.
Thus a PS is a "false" libero: moves up (or sideways) at will but at the back (a defensive false 9/defensive Messi if you will - a #5 as "false 3"
).
He anticipates attackers running towards him much better, cause he sees them coming, and has a view of the whole field (and of the defenders, making him able to communicate much easier). That's why a PS has to have very good reflex, positioning and intelligence (and determination as well of cause), which compensate for the stamina a bit, making him able to play that way for a longer time (it does exhaust a lot mentally, though). He also has to be able to pass the ball really well, cause he's the link between the keeper and the other players (Barcelona likes playing from the back).
It's strange that Pep, Tito and now also Martino desire such players and those are the players that are needed for this system to work…
It's a perfect defensive formation for Barcelona cause it takes all their concepts and just maximises them: the pressing, the possession and reduces significantly the goals conceded. It's the only missing piece to total football, an enhancement to tiki taka in defence. It's also perfect against teams on the counter-attack.
I can understand you thinking it has all these disadvantages, cause you've never seen a team play that way, but don't make up thinks you don't know about. I mean as DonAndres says, no one would think that a false nine is a good idea, but look how it works with Messi. And Barcelona have trained the right players for that, throughout their whole youth system, but just don't know it (yet)!
Our team plays like that, and we almost don't concede goals, and we also like possession and pressing, and playing from the back. Now imagine what Barcelona can do.
