Even in case of 4-1-3W-2 there can be no illegal formation.
Ya, the 4-4-2 is balanced and in this game, this is the best as it is highly overpowered(see my signature). Biggest drawback of this formation is that it has no I DMC and so ur attacking mids *should* be free. And it has no AMCs so u can counter attack effectively against it and can also play offside trap.