Well, as i see some people think that sliders are a bad thing but, for me, it´s the only way to make the game good for all the people taste.
Some prople say the game is too quick, other that the passes are too quick, other that the acceleration is too high, others that shots are too accurated. So, that´s exactly what sliders are for, to adjust the game to personal preferences. If you want to play online of course you´ll use the default sliders, but for offline gameplay you can adjust the game to the best settings depending on the way you play.
All the sports games have sliders, at least all the ones that tries to simulate a realistic sport gameplay, and the reason for that is simply: the default settings will never please everyone, it´s impossoble, so with sliders everyone can adjust the gameplay the way they want.
It´s just a matter of time since we have this on football games, and i am 100% sure that sliders will be avaiable for PES or FIFA on 2011 or 2012. And i´m sure that the same people saying sliders are a bad thing will change their mind once they can adjust the gameplay to their own taste.