Yeah, OK - so you're doing what JMAP does but with a ton of search extension which STILL don't get you cross-folder support. Nice, problem solved - except you don't have a month to implement a good IMAP client, and neither does anyone else in the world.
Has ANYONE ever implemented a good IMAP client, in your opinion? If not, why not?
(JMAP is basically IMAP but more SQL-like, and without a bunch of custom syntax, yay)