Xabi maybe, but not really with Busquets. He didn't do much of winning headers... In fairness, there simply weren't as many long balls, but he, Busquets, was never really a header merchant. Puyol did most of that work.
And you don't have to move your defensive line deeper. In fact you could move it higher and make the CBs challenge for headers instead of the DM.
By the way, Laporte, Otamendi and Kompany are 3 of the best airball challengers in the game. So it would not surprise me if they take up the load of that responsibility.