Just a plea for an optional old-style Curves tool as in ACR 4 (in CS3), but which can be made to come up as the panel of first choice, rather than as it currently appears in ACR 4. If this is poorly worded, apologies.
Other people have requested a levels tool as well. RSP had a nice curves/levels tool that was appled after the rest of the image corrections. I kind of liked that.