I think threephi has some good ideas here.  I can't imagine spending a long time working with the wheel without having the option to set exact numerical values.  My preferred method of using the slider would be to drag the dot around a bit to find a distribution I was happy with and then tweak the values via numerical inputs.  The ability to click and drag on the numerical input box to adjust just that value by dragging would also be extremely useful.

I'd also REALLY like a lock line:  Set a value for one area, let's say economy.  I'd probably go for something that was minimally profitable, generating exactly one bc/turn.  If I locked that value, the dot would then get locked onto a curve so I could drag it back and forth to set the distribution ratio of the other two areas.  I would use this ALL THE TIME.

Nudging with the arrow keys is something that I've found incredibly useful in other places where high precision is important (like photoshop) and seems absolutely necessary for the wheel.

DARCA and MaxWar please, for the sake of the game we all love, discuss your disagreements either civilly or somewhere else.  I don't want my suggestions being lost because the devs wrote off an important thread as done because you two were having a fight.