It is interesting that you managed to get the 32 bit versions of FZ to open in High Sierra. In a way this is good news. It is unfair of us users to request that you maintain the ability for us to keep accessing our 20 year old files but then you always offer such great service, that is one of the reasons we all stick to FZ.
I speak for myself here but all I would like is the ability to open an archived file and re save it in such a way that I can use some of its data in the latest version of FZ. I even wondered if it was possible to have a small application that ran independently from the FZ app that could look for old versions of FZ files on ones disk and automatically update them. I would pay for such an app. Then whenever you updated FZ with a major upgrade you could also update the 'macro app' that would go in and update all old FZ files.
Just to answer Joe's question about running a legacy version of FZ 6. My understanding was that as FZ6 used the USB key we had the right to continue using FZ6 with Leopard on an old machine. Not sure if my memory is playing tricks on me but I seem to recall that Autodessystems gave us the okay to do that?
Justin, I tried running FZ on Windows 10, not for me. I agree with you that Apple dropped the pro users for the last few years but I am salivating over the iMac Pro. I suspect it will be pretty good for rendering but the proof will be in the pudding .
I second Ztech's point that upgrading to FZ8.5 is a worthwhile endeavor.