Well using the Axe since the ULTRA and yet using the Axe-FX MKII, i don't mind to loose the older modeling version. Everybody looks happy with the Quantum 4, i personnally have zero benefits returning to a previous firmware.
It could be managed the old way : you don't like the new firmware, then you goes back to the previous firmware and that's it. Then you wait for a new firmware that please you...
I can understand that some need stability in their setup and want to keep the same basic tone while touring, gigging... but in this case, you simply don't upgrade to avoid surprises...
I've seen major upgrade in the amp simulation since the Axe II has been released, and in the right direction : sounds better, feels better. I've not been spoiled at all and i'm 100% satisfied of my unit.
Fractal made it the right way. I consider that loose the older modeling version isn't a real losse, as the latest firmare is always better. And i still can revert to the previous version if i'm not pleased so...
Stopping FW upgrades for MKI and MKII may push a lot a user to be carefull with their next machine purchase, if i change for a XL+ today, i will probably wait for the Axe III XL also. Double punishment ! Life is hard, but Fractal stuff is good