I'm the guy, too, Gerry! Or, actually mine is the GS645S with 60 f/4 with "cow catcher", not your original GS645 folder with 75 f/3.4. And I agree with your assessment.
I got mine used at a camera show, and several hidden problems surfaced. Incautious buyer! The meter was ok in bright light but non-linear, such that it underexposed in less light. The rangefinder prism/mirror pivot was sticky, and when in for service on these items he found some plastic lens mount parts broken. All this eventually got fixed, but at first I'd been advised RF & meter repair was infeasible.
During that "hopeless" period I got a new Bronica RF645 with three lenses, a wonderful camera. The 45mm turned out the most-used lens, but there were no framelines for it in the viewfinder, it takes an external finder.
So, combining this with a curiosity about AF, I got through eBay a Fuji GA645Wi, motor/auto-everything and fixed 45 f/4. I'm still learning how to run this one. It may not have a "bumper" around the lens like the GS, but its lens retracts when not in use, and a motor extends it when the main switch is turned on. In a crowd I could jostle elbows by poking the lens out!
The GS645S is smaller and lighter than either of these. Pretty much all plastic, and the lens guard hints at delicacy in the mount. But it works very well now,and I don't bang it around. As you mention, the RF is a disappointment with a low-contrast fuzzy edged RF spot. Nowhere near as nice as Leica etc. On the bright side, the framelines both move and change size while focusing.
I find the GS a little slow to use both because of the RF and all the controls clustered on the lens barrel. I've often resorted to setting it from occasional glances at a separate incident meter, and zone focus in good light.
The lens is a honey! The 60mm focal length gives a similar angle of view as a 40mm on a 35mm camera, a favorite and very useful one. And the camera is remarkably small and light weight. Handy to carry. There's also a wide-angle version of this, but note the lens is 45mm f/5.6 and zone-focus only; no RF.
I think you could find a clean GS645S for around $400.