One of the most interesting dynamics in football is how the tactical landscape changes frequently.

SAF was known for 4-4-2 in the papers and such, but he was pretty adaptable, too. I think the shape we see in the papers / media is largely irrelevant though. What really matters is the system and how it plays out, rather than just the formation that the team lines up for the defensive phase.

Historically speaking, United have played their best with 2 strikers. Whether that is 4-4-2, 4-3-1-2, 4-1-2-1-2, 4-4-1-1, etc. it doesn't matter. What matters isn't so much the placement of the players, but how they work together. The key here is having two strikers working together in a partnership.

United's struggles with breaking down sides at home (and away, at times) is largely a tactical issue but I also think there is a squad building component to it as well.

See below for a classic SAF lineup. The player names aren't all the important, I just threw together players I like. The thing to note is the partnerships created all over the pitch. Notice how in this system the strikers can work together, the center mids as well, plus the wide players and center backs. Everyone links nicely and it allows for fluid movement going forward. No one part of the pitch is overcrowded. When you go forward into the attacking phase, you can achieve easy overlapping play, or easy supporting play for quick crossing into the box. You can also hurt teams by going direct through the middle via long passes and quick interplay between the 2 strikers. The point here is that there are options other than just crowing the middle with talented midfielders, or pumping in crosses to the back post for Felliani to hit. Etc.

http://imgur.com/Plc2uS8

You see, today, everyone wants to pack the midfield and play with attacking mids and false 9's and all this stuff. That's great. But you've got to have a truly fantastic striker to win consistently playing this way. OR if you are going to play with 2 wide forwards flanking a "false" striker, those two out wide better be fantastic at creating chances in isolation. OR you better have a player who protects the back 4 like a motherfucker. That way, if you've got a true "anchor" back there you can really allow your wide defenders to join the attack and overlap, thus creating overloads in the final third.

Here's an example of a modern United lineup with Mourinho in charge:

http://imgur.com/wyx3JVU

On paper that looks nice and tidy but the reality is, going forward United are a disaster. You see, if you're going to play any system that packs 5 into midfield, any variant at all, that striker better be a player who can stretch the opposition defense. Otherwise, what happens is the middle of the park, just in front of the opposition's box, gets entirely crowded out. It becomes easier to defend against because teams sit deep and aren't forced to cover any extra space.

If you've got a striker who stretches play, then the other team is forced to cover the space behind them, and thus, the space in front of their box becomes more easily exploitable. The other thing is the wide play. If you've got dynamic players with excellent dribbling and crossing, you CAN get away with having a striker who comes deep. I'm not really a fan of having a lone striker who drops deep in today's game, but if you have the right players to pull it off, it can be incredibly dangerous.

Here's what happens to United's attack almost all the time these days: http://imgur.com/JnjZyn0

See how there's basically no space left in the final third? Everyone sort of ends up in this awkward line of 5-6 players and there's no way through the defense. The wide players have not been playing consistent quality crosses, far from it actually. For whatever reason, they also struggle to dribble past a man and play in any form of isolation. Everyone is drawn to the middle, including one of the holding players, who ends up sort of tucked inside behind the #10 position. It's a mess.

Also note the spaces left behind the team that can be exploited for a counter-attack. There's acres of space for United's opponents to exploit. The spaces are mostly behind the wide defenders and also behind the advancing midfielders. This is a serious problem to have. Against lesser clubs United can get away with this form of "camping" in the other team's final third, but any club that has a decent standard of player should be able to defend against this / counter attack.

http://imgur.com/LPyH1vK

What you see above is how I would LOVE to see Mourinho line this team up. In this system, one that he has used before, like at Porto and Inter, you've got a striker partnership that takes some of the creative pressure off of the midfielders. The wingbacks are instructed to fly forward and provide width. They do not necessarily need to be incredible at crossing because they'll be another target in the box rather than just 1 striker. It's all about having more options and more ways to attack the other team. The midfield would need to be anchored by a massive player who can cover ground and play with discipline. I don't think Ander Herrera is that type of guy. I think he's much better suited going forward, as I've indicated in this lineup. Real Madrid's use of Casemiro has been a great example of this. Without him in their lineup, they're extremely vulnerable.

Also, this would allow United to get the best out of Pogba. He has plenty of energy to help cover the left flank, but he also will have many passing options going forward, AND the stability of a holder behind him. Imagine the 1-2 passing he could play with Miki in the #10 spot, and then seeing him link up further with a faster striker like Martial or Rashford. Devastating!

Finally I just want to touch on squad building.

When SAF was reaching the end of his tenure, United were struggling in Europe, and for good reason. The midfield wasn't good enough. Cleverly, Anderson, etc. Just... not good. So United relied heavily on wing play and that was okay in the league, especially against slower defenders but, ultimately it was becoming a big problem. United had nobody that could cover the defense, and Carrick was sort of left on an island without a real partner. So then United recruit Kagawa, and Rooney begins to play deeper as a #10. I think SAF figured Rooney would be a good enough #10 to create the 5 in midfield that he wanted in order to "modernize" the squad and keep up with City, Chelsea, etc. Rooney is not a playmaker and so this hasn't really ever worked. Kagawa was outcast eventually, and the problems were mostly covered up by signing RVP and winning one last title.

Moyes comes in and brings Fellaini with him. Great. Rather than deploy him in the attacking midfield role, as he did at Everton, he puts Fellaini in the middle of the park, or sometimes even using him as a striker late in games. United still lacked any real quality in the middle and now relied even more so on crossing and wide play. Juan Mata was bought in January, which nobody saw coming, and added yet another #10 to the mix (Rooney, Cleverley, Kagawa, Mata, etc.) without anyone who could hold in front of the defense or be a proper replacement for Carrick.

LVG finally injected quality into the middle of the park with Herrera. I would argue Scheinderlin was a great buy at the time, and LVG just misused him, so that was a big let down. He could have been very useful going forward similar to how Herrera plays (sort of a hybrid ball winner / attacking mid). Ultimately, United ended up selling off their quicker strikers like Welbeck and Hernandez. So now, United no longer had any pace up top, and still relied on wide players to create the majority of their chances. That's not a good mix.

Rashford and Martial helped immensely, but both were relegated (eventually) to roles out wide, for whatever reason. United took what should have been a huge strength, and just added it to their weaknesses.

So Mourinho brings in Pogba and Ibra. Now we've got a truly world-class midfielder, but he's not a holder. And we've got a world class striker, but he doesn't make runs behind the defense. He's what we all hoped Rooney would be as he aged. Ibra is PHENOMENAL but he needs the right players around him to be truly effective. It's frustrating to see how much the team relies on his goals. Pogba has been very good this season, but imagine putting a striker up top who can actually run behind to connect with his passing? It would be glorious.

So this is where United are at the moment. A lot of talented midfielders. A lot of wide players. But a complete lack of ability to break down stubborn defenses. The only way this situation will improve is if United begin to stretch teams using pace up top, combined with utilizing (finally) a true holding midfielder who can help protect while others support the attack.