Q: Mac Mail Needs to be Better than this

I have multiple issues with Mac Mail and I would like it to be a "Best in Class" application.  I'd like to start a discussion about Mac Mail in general.  It has a HUGE installed base and it works well in a lot of ways but there are many annoying problems that should be addressed.  I know a lot of this is personal preference and I am sure my suggestions on specific features are flawed because of unintended consequences but at least the bugs should be addressed.  A lot of these cropped up when migrating from a third party IMAP account to iCloud hosted Mac Mail.  Moving and reorganizing large mailboxes with many messages caused a number of the issues listed below.

• There is no “Mac Mail” forum on the support pages.  Safari and Photos gets one.  Why not Mail?
• There is no status bar or modal window to show you the progress of a large move or copy
• You cannot drag and drop a mailbox into an empty mailbox
• Dragging and dropping mailboxes is a copy by default while dragging and dropping messages is a move by default.  Seems inconsistent.
• IMAP connections stall and cause large transfers to halt with no way to determine what is left to transfer.
• IMAP connections have disconnected with no possible reconnect even though SMTP connections still work fine.  Only a reboot of the Mac clears the stalled IMAP connections.
• You can add an empty sub mailbox but it is not visible in the “Copy To” dialog
• There is no easy way to “unread all” unless you setup a Smart Mailbox for unread messages.  This is difficult to understand for a novice user.  Why not add the “unread” Smart mailbox by default on a new installation.
• There is no right click “Copy To..” option for folders or subfolders.
• There are no quick links to “add rule”.  This would be best as a right click on a message in the inbox.  At least it should be able to be added to the toolbar.
• Exporting a large mailbox (with many sub mailboxes) at the same time as an iCloud Account Info scan causes a fatal error and Mac Mail closes
• iCloud Quota Limits are not displayed.  “Currently In Use” and “Total Available” are blank.  There is no apparent active syncing of accounts.
• The “status bar” is inconsistent. Sometimes it shows “Checking Mail…” but other times it shows Moving Messages.  Many times it stalls until Mac Mail is shut down.
• You should be able to run the filter rules on any selected mailbox
• If I copy an image from one email I should be able to paste it into a newly composed email.
• It would be very useful if you could get some detail on the status line.  Suddenly I see a “Downloading Messages 74 of 337”.  Why?  All I did was rename a mailbox.  Sometimes it says something like “Sending 10 of 10 messages” when I have only just sent one.  The message is disturbing and makes me thing that some virus has taken over and is sending spam.  A right click on the message to give me the details is a must have feature for cases like this.
• Sometimes I’ll click on a sub mailbox and there are no messages.  If I click on a different one and then return suddenly the messages are visible.
• I have seen a case where the Unread Mail Smart Folder is tagged with 1 entry but there is nothing in the folder. Sometimes messages in the “unread” folder are not marked as read even though they have been opened up or responded to.
• The method to open and close the preview pane is non-intuitive and cumbersome to use.  We have to at least add a handle that pops up when the cursor hovers over the edge of the app window.  Best case we would include an optional toolbar icon that can be used to turn the preview pane on and off.
• Every time you add a rule the field to add the rules becomes smaller until it is so thin you cannot click on it any longer and it becomes usable.  You have to quit Mail and restart to get the field back.
• If you add a new rule on one Mac (home) the rule is added to another Mac (work) but it is disabled.  It should be enabled on both Macs.
• In the non-classic layout the sent folder shows who sent the email (me) rather than who received the email.
• If you  organize your Mac mailboxes with rules that distribute incoming emails into those boxes they get lost when you check emails in iOS.  iOS Mail does not scan for unread emails in all of the mailboxes like Mac mail does. 
• Mac Mail generates several No Recipients\No Subject draft emails sporadically.  Not sure why.