Open Discussion → Fancier
Back in the old days, using procmail and mh and em,acs gnus topic mode, I would sort most email directly into the folder where it would be archived, and rely on Unread messages for each folder, with topic mode creating different browsing lists for work and personal, or for different days of the week according to project.
This pleasant scheme was weakened by IMAP - IMAP back then disliked multiple active folders - and relied on emacs' programmability.
Apart from auto-classification, most modern email readers are more primitive: e.g. most nowadays only give you one Archive target.
In Gmail you can remove the Inbox label and leave all of the other labels. But most modern email readers don't really understand labels.
IMAP even now gets bogged down in you have more than a dozen folders you read email from actively.
But I can imagine that my "all subfolders of Inbox are buckets" scheme could be extended so that there are corresponding subfolders inside and outside INBOX. This way, could file directly to the Archive target, and have POPFile see that it was misclassified.