The detail window does show the change, you don't have to open the entire image.
However, when changing the amount or type of noise filtering (Chrominance, Luminance, or all the other possibilities like Fine Tunings/Smooth Edge/Low Frequencies) you need to re-click the image area to get the result in the detail window: in other words, once the detail window shows a certain setting, a new setting change needs to be re-interpolated.
This is unlike the "Sharpening" setting, where a change of USM will show up automatically in the detail window, without having tho re-click.
Hope this make sense and that I expressed myself clearly enough?
As for ISO: yes, we are very conservative concerning ISO numbers, and I can only strongly suggest to compare side by side with the same light and f-stop. One will most probably end up with comparing ISO 100 on the eMotion and ISO 200 or even more on another back, for the same density/exposure: which means in clear that the noise has to be compared accordingly to this.
I have had the same experience that the ISO ratings for the eMotion are much more conservative and generally an average of a stop faster than comparative backs. Also the new noise control in Captureshop makes a big difference in the amount and handling of noise. Although - Thierry chime in here - I still have not been able to get the detail window to show the result of my adjustment, I still have to open the entire image before I can see what the adjustment did, and once open, it displays no additional adjustments that I make. Using CS 5.5.1.