I believe Real Madrid will perform better under Xabi Alonso's leadership, so if Real Madrid takes the Club World Cup very seriously, as you said, I think Real Madrid can win the Club World Cup because Xabi Alonso will want to win the Club World Cup with Real Madrid to show that he can guide Real Madrid to win silverware.
I think otherwise but until then let’s see what come out of Alonso, but imo I do think Carlos is better.. he only just had a bad season that’s all .He failed to sign players when there was time to do it and when the injury challenge came there were no really that much players to replace the injury players(not that there wasn’t though but not as competent as the injured). Xabi could meet all he needs anyways.