Sony has now released firmware version 1.10 for the FS7 which adds some new features such as S-Log2 and fixes a few bugs. The firmware can be found here: http://support.d-imaging.sony.co.jp/download/HXR/OmnLLhp74v/PXW-FS7_V110_firmware.zip?fm=na
As well as adding S-Gamut and S-Log2 I have found a couple of other new things. One is that it is possible to have a LUT on the VF and SDI2/HDMI and have the waveform display shown on SDI2. BUT BE WARNED THAT THE WAVEFORM IS MEASURING THE LOG RECORDING LEVEL and NOT the LUT output levels as most camera do. This is particularly confusing if you are also using zebras to check exposure as the zebras measure the LUT signal while the waveform is measuring the recorded LOG signal. It also means that if you were to use a monitor with a waveform on SDI2 the waveform on the monitor would be different to the in camera waveform.
Regarding S-Gamut and S-log2. There are many very good reasons why S-Gamut3 and S-Log3 was developed by Sony. Key among these are: To eliminate the color shift that occurs when grading S-Gamut, to provide a straight-line log curve that grades easier (S-Log2 is not a straight line log curve in the mid range so grading can be tricky) and to provide compatibility with Cineon and Arri’s Log-C. Do test, play with and try s-log2 by all means, but S-Log2 in the majority of cases will bring little or no benefit to most users and is trickier to grade correctly. I strongly recommend the use of S-Gamut3.cine and S-Log3 for the best results.