For this amount of money, they should allow better use of the storage by making RAW still images storable. It makes no sense that they are selling these for hybrid cameras.
Well, I guess it is all a matter of perspective and needs. If 1080P is all you need, the internal recording option on the a7S does a decent job. If your after all you can get, another $1,300 for a full 4k capability that doesn't overheat after just a few mins is probably worth it.
When you add on how much better the use of a 7" monitor is for accurate live view, the various exposure monitors are for nailing the exposure, applying a LUT to see in advance what your final grade should look like, and recording to 10 bit 422 for color adjustments, the Ninja Assassin becomes a serious production tool if your doing a lot of video work. And I'm still under the cost of the a7S II.
Everyone needs to judge for themselves, based upon their own workflow, but for me I am quite a happy camper. Had I known it would be this helpful, I probably would have bought a Shogun long ago. Since I have no need for anything but the HDMI, waiting saved me $700.