I think it would be great if Location Schemes using the sys_JexlAssemblyLocation generator did not require content items to be in a Site folder. Perhaps the pub_path binding could default to an empty string instead of throwing an error.
I’m essentially stuck using 5.7-style content assembler applications and can’t replace them with 6.5-style Jexl assemblers without spending hundreds of man-hours moving all my site’s content into new site folders.