I think Xabi is an important coach. What they did in Leverkusen is obvious. I wonder whether they will achieve these successes next year. Bayern Munich met with many coaches before signing Kompany, but it would not be easy to convince them, and they could not do it anyway. So they turned to alternatives and signed Kompany
Xabi is actually one of the best thing that has ever happen to Barcelona this season because he managed to bring Barcelona out of there struggling state during the beginning of the season, with his level of experience if they managed to get some more players he would actually turn Barcelona to the way they normally play before and also Barcelona is lucky because his contract with them is still far, so from now till the end of his contract being next year he would have actually reformed the club.
However in terms of Kompany going to Bayern Munich it could affect the performance of the club because Kompany does not really have enough experience to lead Bayern Munich, though I'm not emphasizing that Kompany is not a good coach but I'm just considering the fact that Bayern Munich performance needs someone that has a lot of coaching skills to improve the club more but however let's see of Kompany will make a good impact on the club.