I use PV2012 for development, but I still like to know the status of the raw file. It is not necessary to go back to PV2003--PV2010 with a linear tone curve and the proper baseline offset is sufficient for most purposes and these settings can be saved as a preset. However, ACR/LR always uses white balance, and Rawdigger is useful in difficult cases when the rendered image is clipped due to white balance and the raw channels are intact.
No question that RD is a useful tool in analyzing the data prior to development which can vary. Well worth the $19.95 for the entry level offering. I'm suggesting that for the lesser color geek, gear head, it's not necessary if the goal is to expose and then develop that raw data. It would be useful to see the plots of all the control strips an E6 lab uses to control their process but it's not a requirement to nail your exposure and their development. You do need to run tests, no question. And I'd agree, while it's somewhat cool that there IS highlight recovery in ACR/LR in PV2012 that now actually works, where in the past it was quite ugly, ideally you would not clip any data in case you move to another form of development. As Erik says, it's probably much better and safer to be ˝ or ⅓ stop down than ⅓ stop over even with the recovery. Testing both exposure and development as a pair should give you a very good idea how to do this and the ETTR results should be far better than exposing incorrectly for the JPEG, the crux of this discussion. Lastly, having this true, raw histogram data on the camera is would be the best solution, why after all these years of discussing ETTR don't we have one on all our camera systems?