My two cents: I think a motivated & fit Yaya could in theory do what we're asking Kroos to do, but I have no idea how we could ever know that we're getting that Yaya. I'm not particularly worried about the ground Yaya would have to cover under Pep, and I'm likewise not terribly bothered by the lack of ground Kroos covers. It's more the urgency Kroos has (and that Yaya doesn't these days)... when Kroos gets the ball, he immediately has his head high and looks for the most advanced safe harbor up the pitch. That process happens very quickly. Doesn't matter if Kroos isn't quick in a foot race, the ball is quick up the pitch when it goes through him. I think Yaya has those passes and that ability in his locker, but I don't see him making himself constantly available, and I feel like our play occasionally slows when he gets it (compared to Kroos). If the ball went from backline, through Yaya, to an attacking midfielder in only a few seconds, with regularity, then sure... I'd hear the case. Just doesn't feel like that's always his natural tempo.