My biggest issue with AMDCCCLE is the fact it uses AMDPCSDB. When I was using the binary driver more often I would get very frustrated when I'd manually set something in xorg.conf and it won't work since AMDCCCLE was overriding it. Is there a command-line way to modify AMDPCSDB? Even so, its rather silly (and wasted effort) to have a whole seperate database subsystem for what amounts to a handful of options many of which have xorg.conf equivalents.
As far as a control panel for the open source driver, I'm somewhat surprised there isn't a good driver neutral GUI for that. My only guess is that most drivers don't have a lot of options and they do seem to change rather frequently, so nobody tackled this issue.
Since Nvidia's is open source and takes the right (IMHO) route of manipulating the driver via xorg.conf options, someone might want to extend it to all X drivers, including the open source radeon one.