The big problem with having separate physical, mental and technical PA is that it would lead to
even more unbalanced players, not to mention big problems for the AI in evaluating players' respective worth
Where does a player with a Physical PA 165, Mental PA 95 and Technical PA 130 fit in? What level should he be playing at?
Is a defender with a Technical and Mental CA of 175 and a Physical CA of 130 world class or a liability? What about a midfielder with the same distribution of abilities?
On of the more interesting points you make is that mental stats should be associated with each other and the hidden player personalities a little more (though I don't see loyalty having any bearing on anything)