Xavi shouldn't be playing as much as he has been since the season started, and definitely not as much as last season, but to say he adds nothing is just plain wrong. The team needs him to reach their maximum. Barcelona without Xavi is Barcelona at 50% power. Xavi holds everything together, and this is visible every time he's subbed on or off, or when you compare games with/without him in the lineup. This is not to say that Fabregas or Iniesta or whoever don't add their thing, or that they don't possibly add more at this point (in fact, I recently said I think Iniesta-Busquets-Fabregas is our strongest option at the moment), but I'm just saying, Xavi is still incredibly valuable and irreplaceable and he makes all the difference in the world.