We have a holding player of sorts in Carrick, and as good as Carrick is at what he does, i really don't see him imposing himself on a real midfield beast such as Toure, Dembele or Fellaini myself.
We have been done over by all 3 of those players in the last games we have played against them. So you may be right a proper holding player mighht well make us harder to play through, but we don't have one and that is the problem.
We need someone who will impose themselves in the middle of the park, until we get one we will continue to struggle against powerful players. It's that simple really, and after the success Fulham and Everton had using that tactic, expect more of the same from other clubs. unless we do something about it while we still have time.