Sliders are indeed going to make their appearance in the game for FIFA 12, which will please a lot of people. On the face of it a lot of the things which I feel are somewhat wrong with FIFA do have sliders so you can fiddle with them. I suspect that this area of the game may see some quite big shakeups before release and now, as they do feel unfinished to a large extent. I do have some concerns though, first, as a matter of usability, it feels quite clumsy. There are a good 20 or so sliders, from error sliders and speed sliders to power bar charge speeds and acceleration, but none of these have any reference to them. You have a bar with maybe 50 settings on them, with the default stuck directly in the middle. The sliders at the moment have such considerable play in them, and it's difficult to guess what the effect of the sliders will be (with some it's not obvious which direction on the bar will correlate with an increase/decrease in the effect too). You can set each slider differently for the user and the AI - but unfortunately these are done on two seperate menu with no 'mirror' function, so it's awkward to replicate the settings for both you and the CPU.
Unfortunately at this moment, these sliders are not going to realise the dream of allowing one to fix FIFA or make it more realistic. The sliders do not give you enough control over enough areas to affect things in the way you'd want. For example, if I wanted to alter the passing error, I can only increase/decrease the amount of error. I have no way of dictating what is causing the error, or how that error is represented, and thus if I try to increase the directional error on the passes as I believe should happen, what it tends to mean is that passes become more lethargic and more bouncy long before you get the desired directional effect. There are some tweaks and touches you'd be able to improve, but it's minimal so far, and currently I feel that a lot more thought will have to be put into how these sliders work (or, a massive increase in the sliders available) if they are going to supply the potential for a simulation. I'm also slightly worried that there are a few different sliders right now which affect things like defensive AI (line depth, width, full back positioning and so on). These feel like they should not be gameplay sliders so much as tactical settings. At the moment, these will be things you can use to improve FIFA a smidgeon here and a smidgeon there. They will not open up the possibilities some have hoped for in terms of setting trading to perfect a simulation of the game.
Some of what these revealed was also quite worrying. The passing error slider only affects ground passes, and the shooting error slider does not affect finesse shots. This not only means that the two areas which are probably most wrong (lobbed passes and finesse shots) are not slider-alterable, but it perhaps also implies that the way error is handled on these works in a different way to how it is for normal shots/passes. As both finesse shots and long passes/lobbed through balls are far too accurate, that perhaps is reason. The simple question of why 180 degree clearances with the long pass button seem to land at the strikers feet every time may be answered very simply by that: there is (basically) no contextual error on long passes and chipped through balls.