I somewhat agree with you on the Mamiya 7. Oddly, I absolutely love the slightly older Mamiya 6 and MF version of that system. Slightly different in design and construction, but Oh, so different is use/feel in my opinion.
Of all the cameras I've owned (from Canon and Leica 35mm up through Canham and Phillips ULF cameras) the one I regret selling the most is the Mamiya 6 system that I had.
...and I almost bought one again this winter, but the electronic shutter in the system has me convinced that they won't be long for this world anymore, so I bought a Hasselblad and also a Rolleiflex 3.5f.
I pondered the various Rollieflex options when choosing and ultimately decided that I liked the metered body and if I could get one that worked well, it would allow me to be super-simple with my kit when I wanted to go that route. It seems to be a great system for that. Much lighter than a Hasselblad, but, of course, much less flexible. I also liked the interchangable VF because I felt it may give me options for a prism and other screens that may be handy. I'm not experienced with it yet to know how I'll use it, but straight out of the box (with the original Rollei focus screen) seems to be a fine shooter.