TBH he actually is a decent manager for those small teams who want to avoid relegation without having a much troubled season, but from mid-table up he's simply not good enough.Not a Premier League standard manager. This was always going to happen.
In those biased articles the media highlihted that he won the Cup with Sporting, which is not really a big feature and Sporting football quality was quite poor, since they actually had a very decent squad at the time.
At Olympiakos not surprising either, the rest of the greek teams barely had money, so Olympiakos would always win the league. Now PAOK has some funding and things are geting more balanced.