In a typically magisterial and insightful piece, Arsenal Column has laid out the strengths of the 4-2-3-1/4-3-3 formation as used at this year's World Cup by numerous teams as well as by Barcelona. The stability offered by using two deep, holding midfielders to occupy the space in front of defense has certainly become a popular formation. As the Column points out, Arsenal have enjoyed some of their best runs when employing two deep midfielders (Vieira and Petit, Vieira and Edu, Cesc and Gilberto). Last year's use of Alex Song was a little different, and potentially problematic:
The previous season, Alex Song was often left isolated in what essentially was a 4-1-4-1 formation and Wenger found that, if a team bypassed the first wave if pressure, the Gunners could be exposed in the centre. The revitalisation of the two in front of the defence should give Arsenal greater structure in defence and organisation into four easily identifiable bands.
Arsenal look at their best when using another holding midfielder alongside Song (or whomever is given the task of shielding the defense). This preseason, Jack Wilshere has featured in a deep role alongside Emmanuel Frimpong, and the pairing has worked well.
Spain, at the World Cup, used Xabi Alonso and Sergio Busquets alongside each other defensively, Busquets winning the ball back for Xabi to distribute. The holder/passer/creator midfield triangle for Spain (and Barcelona) functions very well for quickly converting defense to attack. As has been discussed here before, Arsène Wenger can set up Arsenal's midfield talent in any number of possible combinations within this system.
It is important, though, as Arsenal Column points out, that he does not isolate Song in front of defense, as Arsenal's two attacking midfielders often leave gaping spaces behind their runs which good teams (Manchester United, Chelsea) exploit on the counter. If Abou Diaby or Cesc Fàbregas plays alongside Song, taking the passer role, and then respectively Cesc or perhaps Samir Nasri plays in the more attacking, creative role, it should limit the space for the opposition and allow Arsenal to quickly shore up their defense when the other team is in possession.
Such is the attacking talent for Arsenal that using two attacking midfielders is probably overkill; scoring goals (as long as Arshavin isn't forced to play center forward) will not be a problem. Limiting space behind the attack should be Arsenal's priority this season, and Wenger looks to be moving in that direction based on the evidence from the preseason fixtures in Austria and at the Emirates.
Anfield will be the true test...