I recall saying even in Joe's best times that his kicking was a major flaw in his game. How many times did we see him boot it into touch when misdirecting a clearance upfield?
The genius that is Pep didn't have to be the genius that is Pep to spot this straight away. There had to be a clear sign that Joe couldn't (or wouldn't) change his game, hence Pep ditching him pretty quickly. Other managers have since acted in a similar manner, so Joe's demise has been dramatic, if not surprising.
That having been said, it's a shame to see his career nose dive. He was one of a great group of City players who brought us our first major trophies for donkey's years. He also had many tremendous performances for us. Personally I wish him well.