For instance, most of my mail is sorted into labels, skipping the inbox. When using a mail client with IMAP, these labels shows as folders. Deleting the mail from my client, doesn't delete it from Gmail, only removes the label. Useless.
However, along these lines the removal of Jabber support from Gmail is a little bit scary (first they removed federation support, then they killed it altogether). Limiting or removing IMAP is not outside the realm of possibilities.
> However, along these lines the removal of Jabber support
> from Gmail is a little bit scary (first they removed
> federation support, then they killed it altogether)
My understanding is that upgrading to Hangouts still disables the old XMPP support.
> My understanding is that upgrading to Hangouts still
> disables the old XMPP support.
And just for added measure, deleting the label seems to me to be the right thing to do.
However, most IMAP clients expose mailboxes as "folders" and barely support flags at all (no indexing, not even slow search, no UI at all most of the time, and if it even bothers to parse them, often has some silly limit like "five flags that must be configured ahead-of-time in Settings"), so users would have had a totally useless experience.
In essence, Gmail's IMAP is implemented the way it is not because it is the best way to map Gmail's semantics on to IMAP, but because it provides a reasonable fit to the way Outlook, Thunderbird, and Apple Mail (the only e-mail clients that have any marketshare) represent IMAP. Those clients represent trees of mailboxes as a folder hierarchy.
While commonly believed, people really need to stop blaming IMAP for Gmail: it's about as silly as claiming using HTTP headers as part of an API specification is impossible because none of IE, Firefox, Chrome, or Safari, allow users to modify the headers in their document-oriented web browsers.