ETTR should not result in reduced saturation. The issue is that most applications don't expect ETTR files and produce undesired results.
For ETTR to work properly, the exposure compensation in the RAW converter must be a simple linear scaling of the raw values before any non-linear processing. This unfortunately, is not the case in ACR/LR, especially if you use process version 2012.
In my limited experience, RAW therapee allows scaling of raw values before demosaicing/processing, but it can be a difficult tool to use.