i think PES(or FIFA, for that matter) should have a system where you can switch 'button modes' for the player you control, especially in loose-ball situations. Let me explain :
Suppose you are in possession of the ball, and misplace a pass to your teammate. Now, your teammate and an opposition player converge on the ball, and it's clear the opposition player will win the race unless your player slides in to try and win the ball. However, seeing as the last touch on the ball was by a player on your team, the game believes you are in an attacking position and a sliding tackle is impossible until the opposition player touches the ball. What I would like to be able to do in this situation is to press a button(say L2) and press O(for PES), and the game recognises the button press for a sliding tackle rather than a long ball.
The same switch should be possible for changing from defence to attack. Normally the game engine does a good job of recognising game situations(in PES2, I haven't played a lot of FIFA recently), but every so often you feel that you've been robbed of an opportunity that you might have taken advantage of in real life.