I think he was vastly overrated, due largely for our desperation at the time for our academy to produce a decent player. Thought he was very useful from attacking set pieces but he was a very suspect defender. He was shit at QPR (relegated) and shit at Cardiff (relegated).
But you might be right about being coached properly, take a look at Carroll who at the same time as Caulker both were being heralded as our greatest prospects. Carroll has remained, knuckled down, gone out on loan, come back and whatever he is doing on the training field has earned him selection in the team and now he is starting games too. I bet his wages are 75% less than Caulkers though, but Carroll's career right now is on the rise. (But if Caulker get's a move to Newcastle as rumoured, then he might have the bigger smile on his face still, or alternatively he can go for the clean sweep and get relegated with Newcastle too).
EDIT: Just seen the links to bin dippers, fuck he has got a good agent.