Found some info here
http://www.bundesliga.com/en/liga/news/2013/0000282349.php
Leverkusen had the 2nd best defensive record with him in charge and played a 4-3-3 (with Defensive midfielder). Also seems to have a knack with young talent.
One rather interesting sentence "Replacing lost talent...
Did anyone actually watch/see how Leverkusen played while he was in charge? Or know anyone who did?
Going off one sentence he made about last season whilst helpful, doesn't really give us the answer.