The Swiss Marcel Koller introduced a 4-2-3-1 system, flexible enough to become 4-3-3, at all age-group levels when he was appointed in 2011. STRENGTHS David Alaba is the star name but the whole midfield deserves praise, with the more defence-minded Julian Baumgartlinger and the dynamic Zlatko Junuzovic equally important. WEAKNESSES The back four is sometimes…