One of the worst AI is when you have to cross the ball, be it corner or in play. The MC ones are useless. They make horrible runs, always to late and leave all the space open outside the box to make it so easy to keep possession when defending and having to clear the ball.
They also need to sort out the fullbacks stat. They like nothing better than to keep players onside, don't help when they should. The ring button never applies to them and it's so hard to change a player to try and play them. By the time you do play them either the moment of pressuring time is over or the winger has made his run successfully.