If we're rubbishing Lambert as not being good enough then we're using pretty unrealistic standards.
He had at least three good seasons with Norwich - back to back promotions then joint-10th in the Premier League before he left to go to Aston Villa. Outside of Villa he's had more success than failure - a terrible spell at Livingston, decent at Wycombe, good at Colchester, short half season stints at Blackburn and Wolves which were neither particularly good nor bad.