Derby did what they always do even under Lampard. Faltered and stuttered all season and failed at the business end. It happens every year and Lamps was no different.
This after huge backing and funding. Ashley Cole would have wanted a princely sum to turn out for them.

It's the Managers job to get the best out of the players and produce consistently good results.
He wasn't able to do this so I don't see how he could be considered a good Manager