I'm not sure I see the problem: 'Export', and 'Export as' works as 'Save' and 'Save as'. This i like 'Export to PDF' in a word processor. If you never save in GIMP, I suppose you don't use layers?
I do use layers sometimes. But all of my input and output images are PNG, TIFF or JPEG and I have no use for the intermediate state. XCF is a non-standard application-specific format which has no use other than with the GIMP. It has its place, but the assumption that it is the central part of the workflow of end users is simply incorrect. It wouldn't have caused so many complaints if it was the case.