Which strategy are you using? Try switching to control or attacking. I think rigid philosophy is a waste of your players' talents, if you go more fluid with good players they are capable of seeing openings and taking advantage of them at the right times as well as covering when someone moves out of position. Rigid is a more defensive mindset so that you don't lose shape and players stick to the formation...since you said scoring goals is the problem then ditch that.
More direct passing will help open things up, especially when playing on larger pitches. I would leave focused passing on default/mixed and use the appropriate exploit the flanks/middle shout when you go up against a team that has gaps in their formation. Playing wider and with a higher tempo (which is part of the control/attacking strategies) will lower your possession % but you'll see more chances and score more often. You can play narrower late in the game when you are trying to protect a lead.
I think 3 having playmakers is too many cooks in the kitchen. Try this:
Song - Defensive Midfielder/Defend
Fabregas - B2B
Denilson/Muntari - Ball Winning Midfielder/Support
Ozil - Adv Playmaker/Attack
van Persie - Deep Lying Forward/Attack or Support
Aguero - Trequartista
Aguero target man to feet if you want to make him the focal point. Good luck and let me know how it goes
