Another splendid argument.
Okay, first of all; both Cambi and Masch plays on teams which plays alot more defensive than ours, which leads to second; because of both Inter's and Fools' more defensive strategy/play philosophy they often attend to play with two defensive midfielder (Xabi Alonso-Masch, or Masch-Lucas, and at Inter Cambiasso-Zanetti, Cambiasso-Vieira, Cambi-Chivu etc), which means that Cambi and Masch always got an partner to cover the midfield, which means that they have smaller areas to cover, which does their job Alot easier. Yaya on the other hand plays on a extremely offensive side which plays with 3 strikers and 2 midgets in midfield, who aren't exactly the best defenders/tacklers.. So, the area Yaya covers is twice as big as Masch and Cambi's, which makes his work ALOT more heavy and difficult, and together with that, he is the link between offense and defense, which he does in style..
Yaya is stronger and faster than both, and often have to cover for missing defenders as well.
And that's all for me, for now.
edit: Masch is a pure DM, which he is good at, no doubt, but both Yaya and Cambi can offer something in offense as well.