In a sense, this is another instance where one has to step back and evaluate the gain and loss of a new offering based on very personal criteria.
A friend and I were just discussing this yesterday. In some cases, a new offering presents a clear alternative rather than an incremental one. At the rarified price category of many new Leica offerings, it is a serious consideration.
I think the MM presented a clear demarcation, an easy one-of-a-kind decision for those more dedicated B&W rangefinder shooters with the means. I saw the S2 as also being a clear "yes or no" decision based on personal applications because the form factor, dual shutter, and all new, ground up S lenses ... also made it a one-of-a-kind solution. Similarly, upgrading my Hasselbald H3D-II to a H4 was made easier because of the addition of the remarkable True Focus innovation, and a Dalsa based 60meg CCD with its delicious skin tones.
In the case of the new Leica S camera, the gains are incremental at best with little evidence that one's photography will obviously be impacted. Same for the New Hasselblad H5. Incremental at best. Neither represent inexpensive decisions.
For some, The new M is as revolutionary as one could expect from their flagship rangefinder camera. For others, the demarcation from CCD capture, to CMOS and its attendant added versatility, is a loss that worries them based on personal criteria, and IQ expectations they formed with the M9/M9P.
In addition, I personally do not subscribe to the M's size creep to cram in more e-features. Personally, I would have loved a new CCD dedicated rangefinder M that was smaller than the M9. For performance, there is no reason that the Maestro Processor couldn't have been used with CCD, (the S2 with Maestro is CCD). I also think more high ISO IQ could still have been squeezed out of CCD. Weather proofing, and all the other little tweaks? Sure.
-Marc