I can't comment about players I never saw playing - Lothar Mathaus is ranked as the best box-to-box defensive midfielder of all time but I only saw him play in the 1990 World Cup and at the time, my understanding of tactics was juvenile
Defensive Mid - Roy Keane (Vieira a close second)
Box to Box Mid - Clarence Seedorf (Gerrard a close second)
Playmaker - Xavi.(Scholes and Pirlo a close second)
Attacking - Zizou (Iniesta comes a close second)
I think it is impractical to compare players of different generations IMHO
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