This is from my short experience with a few good cameras, but no TLR's.
I too have similar questions about MF, and actually I am so deep into LF that I rarely even want to pick up a MF camera.
On the MF side, I really feel that you need 2 MF camera systems.
One lightish RF like a Mamiya 6, Mamiya 7, Fuji GSW/GW690 or a GA645zi (if you want auto everything) for light travel, hiking and a grab and go camera, for landscapes etc. Actually the ZI is pretty cheap for what it is. For now I have settled on the ZI, but I sure wish it was a 690 format.
Add to that a versitile MF slr or maybe a tlr like the mamiya c3 pro. Something you can put on a tripod (plus mlu for a SLR) or handhold at a higher shutter speed, and actually see what you are framing. Of those I think the Pentax 67II, Pentax 645ni fit the bill. Maybe a Kowa, just because they are so cheap. There are a multitude of other cameras out there too, like your camera. Did you ever get a chance to try another lens on your camera with B+W pan film, MLU on a good tripod ??