A so-called experienced FAA PPL holder was so utterly dreadful that we couldn't send him solo. He let the aeroplane fly him rather than him controlling it; I can only assume his continued existence as a pilot was more by luck than by judgement.
Beagle - Can't you find any UK PPL examples ? Funny how it's always the dreadful FAA PPL who is always so crap. Or is it your perception and prejudices that colour your filter of the outside world.
My perception is that there is not a major problem, most FI's, are hard working, focused individuals doing a good job. But then again I am one myself so my perception might be clouded - But then this is an Instructors Forum.