I was sold no platform... I only bought a (another) back that had no alternative out of incapable back makers...
H6X would offer a better future plan for the pro... I always make my upgrades under a pre-decided plan... don't you?
Actually, i would call a CF & the CF-MS a platform all it's own, unfortunately they haven't touched it since the -39 chip. I understand your want for it, as it gives ultimate flexibility that has never been matched. Given the consolidation of camera systems down to Phase and Hasselblad, there isn't as much motivation to do a platform such as the CF, especially how multi-shot is a subset of H system users.
I think I'm reading into your statement as that buying a H6x with the idea of upgrading to a Hasselbad 50c MS or 200c MS back at a later time. I would actually say someone is better off going for the cheaper H4x/H5x, or saving money for the purchase of the newer back.