For my tupppence worth, over 90% of the pilots who winge about EK Training and Trainers quite simply haven't done their work and preparation properly and are looking for an excuse because deep down they know that it was nobodies fault other than their own.
For guys that do OK and still complain it's normally because they are comparing it to their previou airline/experiences. YOU'RE NOT AT YOUR PREVIOUS AIRLINE, GET OVER IT!
Regarding bad trainers/personalities, yes, there will always be some in any airline. I suspect the 777 fleet has a few more than the airbus fleet, but on the airbus side I can only think of 1 that shouldn't be there.