It seem that reading this topic it has been drawn to a health testing debate but regarding the op's original question I think it is fair to say that not every pup out of a litter will get the same upbringing, who is to say that the gamekeepers pup would not come on to become a FTCH if trained to do so ? and on the other hand the pup from both FTCH parents goes to a home as a pet and is everything the owners could ask for ?
A bloke once asked me about little Syds pedigree and he was quite impressed but he did say it would be his parent's parent's that he would want to look at. Maybe there is too much foucs on having ftch throughout a pups pedigree and not enough planning on the enviroment, rules etc in which the pup grows up in.
As for a pup with lots of ftch in it's prdigree not being easy to, I have to disagree both Lilly and Syd have been very easy to train. I think to the point were Syd has almost taught himself. You will not go wrong with a working cocker, like everything else in life "you get out what you put in"
Smokey