To get the best out of a Diamond. You get to right ingredient/factors = right players and top level.
To get the best out of a top super car. You get have perfect wheels. Every ingredients have to be on top level.
And to understand the diamond formation. You get to know what it needs in all positions. Special the 3 men midfield. It’s the engine of the team. You get to have it right.
Now i will explain what it need and demand.
RCM - DCM - LCM
DCM = Deep laying playmaker. Really good to dictate and control the game from the deep. And beside him he has to creative runners.
RCM & LCM = Two creative runners. They are better with the attacking and the creative. Ideal and perfect RCM and LCM = Iniesta, Xavi and De Bruyne
City 3 CM = Da Silva - Fernandinho - De Bruyne
Prime Barca = One of the 3 in the history = Xavi - Busquets - Iniesta
Ask yourself. Are De Bruyne, Iniesta and Xavi deep laying playmakers? How were those 3 as a players. Aren’t they midfield runners?Make run and pass players from midfield to attack?
And the CAM is a central attacking midfield player. The link between midfield and the two CFs. A free role in the attack and behind two CFs in defensive.
Now. The question now is do United have the players to suit the diamond?
My answer not the highest level of a Diamond. But i think good enough to get top 4 and close to the best. But everything need time to gel and to work out. Things take time.
Mine rating and analyzing of United squad to suit the diamond. Special teams who sit deep. Is with this line up.
DVBeek - Matic/Fred - Pogba + Bruno - Rashford - Martial. Just let them work and gel together.
But against top teams in premier and Europe. I might go for 451. So stay compact and close the wide sides. Against teams United shall dominate most of the match. Diamond formation will suit better. You have 2 CFs whose will stretch the opponents defend. But against top teams. I am not sure United are ready to dominate the yet. Then counter attack. Stay compact with 3 really quick attack players is the answer. Like this :
Greenwood/Mata - DVB - Fred/McTom - Bruno - Rashford + Martial. With this line up. The key is when United break up opponents attack. Then play it up on the left side to Rashford or Martial. Most of United midfield players are right foot players. So it will be more easily to pass it to the left. Then you have a quick Rashford to combine with Martial. DVB and Bruno are quick too. So with this counter attack. I think Bruno will suit better than Pogba. Because Bruno usually is using few touches than Pogba and normally a bit quicker the ball and delivering of the passes.
This 5 men line up and combination might suit against parking bus teams too. But i think the Diamond with 2 CF and a CAM will suit better. Because Rashford is better as a CF. Rashford is been able to drible some CB in the box. And Greenwood is not a natural RW too. So...against top teams. Teams, those will give United space. Then super speed, good ball skills and a sharp and clinical finish what its needs.
So sum up and conclusion. Again, to make a diamond shine. The ingredients and players have to be right. As highest level as possible. Then the diamond will shine and works.
BUT. If you have a top quality RW. Then the 4231 can be ideal and perfect too. Special with Sancho. Like this:
Sancho - Bruno/DVB - Martial + Rashford. Against tight defend. Maybe with McTom - Fred/Bruno as the 2 cms.
Against top teams in Europe:
Sancho - McTom - Bruno/Fred - Rashford + DVB/Bruno - Martia/Greenwood
But now United don’t have Sancho in the team. A really good and natural RW. So depending on the level and qualities of the opponents. I will switch from diamond and 451 formation. I like 5 men midfield to close the wide side. And 451 make it more clear and easier to press as a team. Then the wide players can press opponents players with the ball into the middle. Where it is tight.
That is why i think and believe diamond or 451 will suit United best. 4231 with Bruno as a nr.8 and Greenwood as RW will work too. Against teams United shall dominate like this :
Greenwood/Mata - Bruno - McTom/Fred - Martial + DVB + Rashford
With the addition of DVB. I think you can Bruno a bit deeper, as a nr.8. Beside a nr.6. A defensive one.
So again. It depends really on the qualities and level of the players. To make all formations work. Beside really good coaching on the training pitch. Gel the players as a strong unit. Beside individual skills.
In the end. You need the important invisible factor too. Like luck. Really important. Beside good and right football decision as most time as possible on the pitch. Lesser poor decisions and mistakes.
All the factors and ingredients have to be in place. To make a bigger picture that is calling success and becoming the best. There are more beside football factors and ingredients. The bank of luck....has to be deep and big.
A lot of money to spend = good luck and karma. And winning and fighting mentality factors too. So the diamond and formations are clearly not the only reason and ingredient. Behind a team success. All the puzzles have to be in place