Everyone has to make their own decisions, but for me, those other imrprovements aren't worth very much. I've had my FS7 for about three years now and I don't have any trouble at all with the design of the viewfinder or the lens mount. And adding more Assign Buttons is pointless unless they also add more functions that can be assigned to those buttons. I already have more buttons than there are possible functions that I want to assign to them. Variable ND would be great, but that, along with the rest of the improvements, don't add up to $1500 for me.
For other people, the FS7M2 might be worth the extra cost, but not for me.