ok, 'search that does not suck' isn't a feature of IMAP.

> Filtering doesn't belong at the IMAP protocol layer anymore than it belongs at the SMTP layer.

Right, so users are forced to set up this stuff for each and every device they have. This is a big reason why the exodus to webmail and the proprietary internal-only protocols they use.

Seive is really powerful and I've used it plenty of times, but it's not standard and is something that needs to be done completely separate from almost all email clients. Unless you are a big email nerd that runs your own servers it's pretty much worthless.