The playmaker control in the manual is refering to when you are the QB and are trying to get your closest receiver to make a change in his route running... With that said, I don't think it is working in the game.
You are correct about the L trigger being used on Offense to pitch the ball to a teamate, which seems to be working, although I have not been able to do it on Co-Op which is where I would want to use it the most... ie, making my own reverse plays... especially on kick offs and punts, it hasn't worked and it looked like there was such a possibility for custom plays while using it... oh well..