Hello and thank you for choosing JA for your support needs. I am truly sorry for the issue.
In essence you are asking for a Professional Opinion on whether you should downgrade to Windows 7 or keep Windows 10. In my Professional Opinion I would say to Downgrade back to Windows 7. As it is a proven and stable platform for you and worked well with your device. Until Microsoft and Canon get the needed processes in place to allow for a "Seamless Upgrade Path." I would not upgrade until all issue's are resolved. Also, it may take a few months (If you like I own a business. Then that is time that you cannot afford to waste.) before they have a driver that is fully compatible with Windows 10.
If any more assistance is needed please chime in or we can always chat via the phone if you wish.