"It is the decision to release lenses which still cover 6x6 which is making the wide angle difficult."
There are two things regarding the decision to use 6x6 lenses. One is the image circle. As an example we can see the difference in FX and DX lenses from Nikon.
FX lenses operating on DX sensors are bigger, more expensive and less efficient than similar FX on FX sensor. Hy6 decided to go "FX" (66) when sensors are DX (645) and other systems are DX-DX (645-645)
Fine, they can do two things a) wait to hit the lottery with FX (66) sensor and/or make, say, a 28mm DX -- note that I use DX and FX just so that I can get understood --
But ther is when the second factor will apply, that is: the larger distance from "film" plane to placement lens element that has to clear the movement of the mirror.
In other words, a Hy6 28 has to be more retro focus than the equivalent 645 equivalent --even it it is a reduced image circle or DX--
If you see the size and cost of the two reflex 28mm lenses in production you can tell how difficult it already is (for 645) to formulate optics that perform at the higher than film expected standards of 49 mp backs.
If you say "Actually a rotating back makes no difference to the size of the image circle" then it means that having a FX format is even more of a gamble -- because the designers could have gone 645 AND produce a rotating back -- since there is no sign in the horizon of Kodak or Dalsa sensor appearing any time soon on 6x6 size.
But suppose they one is developed, Sinar has to make a new back for the larger sensor. You have to take in to consideration that a 6x6 sensor will not replace 6x4.5 format, it would have to fight against it to get adopters, which brings us to the square format. I personally like it, but it is not the "standard" proportion but more like a station wagon, or hatchback -in car analogy-
So, the Hy6 will steel missing wide angle lenses --unless you upgrade to the new square format-- The high cost of producing the larger sensor back will have to be absorbed by a very small potential user base and we don't even know if existing lenses will be good for a full frame sensor since none exist today to run tests.
Regarding Steves comment, I think he is correct in considering Mamiya the value choice, but remember that not so long ago in the film era Hasselblad was the king of medium format until the RZ came and became the choice of a large number of the top photographers not only as the value work horse but also as a better camera because of the rotating back, bellows focusing, leaf lenses and size and proportion of the 6x7 format. Phase One used to have the lion share of the digital backs, so the two together should not be dismissed before the race has even started... i think
"H system is a closed architecture nothing positive"?
On the contrary, there many positive aspects to the "closed system architecture". More critical focus due to focus adapation and known placement of the sensor in relation to the camera, automatic correction of lens distortion, apochromatic aberrations, and vignetting, etc. My customers find these aspects extremely positive.
There is much positive news on the Hy6 as well. It accepts digitally adjusted Schneider AF lenses, employs a fast and responsive AF system, provides ergonomically advanced camera controls, and will continue to benefit from digital/camera integration into the future.
While I think the Mamiya AFD is a fine camera - I am a Mamiya reseller, and the Aptus 65 with free Mamiya AFDII is a great value right now - let's be honest, it's always been the "value" choice, not the preferred solution. While H2 cameras were in production, they outsold Mamiya cameras by more than 3 to 1 in the US, despite the higher price.