Johannes, welcome to the forum!
Indeed very good to see DHW active here! For Hy6 system there is thereby online support from both Johannes and its Leaf backs from "Yaya" Yair Shahar in these forums. Not sure if there even are any others from any manufacturers on this forum. It is a good very good ting with this support. Hopefully more people will realize how good these products are.
Really good with upgrade option of older Hy6 backs, much different from what Mamiya was to me.
I also wished for a p45+ when I had my 6008AF and I guess it was possible through Rollei Metric/Trimble for and extra 3000euro. But two big things changed how I feel. First I can work the Leaf MOS files in capture one software which was big, and secondly Leaf introduced the AFi-ii which has the revolving sensor which I use very often. To be able to rotate from landscape to portrait in two seconds without looking, and keep my focus on shooting without chance of dust or dropping. This is really very important to me! The ergonomics on the Hy6 are very very good, and the rotating sensor of the Leaf AFi-ii completes this package. Now I view the leaf credo and phase IQ as being nearly the same and I'm happy that they are supporting the Hy6 with two options. A third would still be okay
+1 If Phase One backs were offered to Hy6 it would likely attract more users, and also match Phase One's open system policy...
Yet... per my humble experience I must also ask why Phase One? My Leaf AFi-II 12 is already so very good image quality and is on pair in image quality to the IQ180, but significant lower priced, rotating sensor, tilt display, larger display. Leaf support is superb to me, both locally in Hong Kong by Gavin Hui and Fai & Peter in FounderGT/Leaf in HK, plus by email to Yair. It is not about gear raving, it simply works so really really well.