So what do you do when playing 3-5-2 against a team who plays with wingers and attacking fullbacks?
Say Juve play Bayern:
Buffon
Barzagli-Bonucci-Chiellini
Isla-Vidal-Pirlo-Marchisio-De Ceglie
Matri-Vucinic
versus
Gomez
Ribery--Muller--Ribery
Schweinsteiger-Gustavo
Alaba-Badstuber-Boateng-Lahm
Neuer
If Ribery and Robben are high up, Isla and De Ceglie are likey to play them, rather than a CB stepping out of position that early.
Then Alaba and Lahm start to join in th attack. Who is going to confront them? Does a striker try to track? Does a midfielder go wide? Does De Ceglie step forward to meet Lahm and look for Chiellini to pick up Robben?
It's not a question I can answer. Being overloaded on the flanks is the key defensive weakness of 3-5-2.
And when Juve try to attack, should Isla and De Ceglie go beyond Ribery and Robben and leave the team exposed to a counter attack? Do they stay goal-side and leave Juve basically playing and back five and offering no width in attack?
These are big problems for 3-5-2 when playing against teams who play with wingers.
There are very few wingers in Serie A, so 3-5-2 is fine.
Does it no occur to people why almost no-one outside of Italy plays 3-5-2 just now? It's because so many teams are playing 4-2-3-1 type systems, with wingers of some sort, so the problems I have mentioned for 3-5-2 would have to be dealt with by a team playing 3-5-2 every week.