I disagree with ur comment on Ibra being a bad signing, as we all saw in the Barca's game against Hercules at the start of the season, Barca could not manage to get the ball into the box, if they had Ibra they could have reverted to a plan B and gave him long balls to chase, Ibra always added a extra dimension to the Barca attack and he did decently too, no idea why he was loaned out
Masch is needed as a sub in games where Barca are trying to protect a narrow lead, Busquest does not have the physicaltiy like Masch to break up play and get stuck in, Masch can also be used in games such as against At Madrid where he is required to track the physically imposing Forlan by dropping deep and nullifying him, as Spanish football is more on techinality and not as physical as English Football, Busquests is able to perform his role admirably, i doubt he can reach the same heights in English Football but that remains to be seen and is a debate for another day