Comment 22 for bug 122529

Let me post here my thoughts.
Realistically, the IMAP interface for GMail is very different from a normal one.
It seems to me that ideal client behavior would be the following:

The spam filter be disable for just the Gmail account. For many people Google's own spam features are enough, and TB's on top of it just adds complication. Obviously it should be possible to use it if desired. Either which way, the "Junk" button in the interface should move the message to [Gmail]/Spam.
Ideally, when in the [Gmail]/Spam folder, the Not junk UI feature would be availible, which would IMAP "move" the message to the Inbox folder.

Sent mail should be copied to [Gmail]/Sent Mail only if the Gmail Smtp is not being used.

Draft messages should be saved to [Gmail]/Drafts, and messages in that folder should be recognised as drafts, allowing them to be open for continued editing.

All Special delete handling such as the keeping a local copy of deleted messages should be disabled. Those features really mess with GMail's IMAP features.
The button that sends the IMAP delete button should actually have several personas. When in the Inbox folder, it should be labeled "Archive", when in a tag folder, it should be labeled "Remove Tag", and when in the in the [gmail]/Trash or [gmail]/Spam folder it should be labled "Purge".

A new Interface button should be added labeled "Delete" that simply Does an IMAP move of the selected messages to [Gmail]/Trash. This button should be disabled in the [Gmail]/Trash folder and the [Gmail]/Spam folder.

Finally, a new interface button labled "Tag" should be added. When clicked it would display a list of the IMAP folders, possibly excluding the "[Gmail]/*" folders. Selecting a folder would result in an IMAP "move" of the selected message(s) to the chosen folder.

If all the above were done, the interface would be highly sensible and work well. (Except for errors on my part due to misunderstanding the gmail IMAP equivalency chart). as it stands right now, configuring Tb to do all those things is almost impossible. Some are easy enough to do, but others basically need extensions currently.