Ful support for G-Suite accounts including resources (e.g. meeting rooms) when making appointments in the calendar.

Would like to be able to accept or deny approval emails for DL emails as I can in the browser or the Windows client. Most annoying as I need both the browser and Mac client open.

This was lacking in the original Outlook for mac, but still think it needs to be done. I like placing the reading pane on the right. With the message list, I'd like to see the option of adding additional columns to quickly sort by. This is one of the features I use so heavily that I still find myself using Windows-based Outlook on mac.

Instead of breaking them by Today, Yesterday, Last Week etc, I would like to be able to them as a list with a proper Date column

The web client has the ability to style text as a quote, while the Windows client has the ability to add standard styles (Heading 1, Heading 2, etc.) which is similar to Windows/OSX version of Word.

It would be great to gain more style formatting options in this new Outlook for Mac.

I use flags not just for follow ups but to help categorize items. More colors would be helpful.

To prevent accidental message deletions, allow me to remove the Delete button that appears when hovering on messages in Inbox.

Ideally, I could customize which buttons appear when hovering using a dialog similar to the toolbar customization dialog.

When the mouse pointer hovers over a message header, action buttons (Delete, Archive and Flag) appear, making it very easy to click on these buttons by mistake while trying to select a message to read.
I believe the buttons are helpful, but it would be better if they were always visible and I would suggest either the far left or far right of the headers to place them.

favourite folder bar next to the toolbar

When viewing the Flagged email list, scrolling causes the scroll bar to appear and overlap the Flag icon making it easy to inadvertently click the scroll bar (causing you to scroll half way down the list) when you meant to Flag or Unflag an email.

Be able to reduce the whole window to a single pane view listing last 5 emails, next 3 calendar appointments, and month calendar view. Kind of like the right calendar strip with minimized emails at the top

Attachments, when saved to common user-facing folders (Downloads, Desktop, etc.), should have their permissions set to read and write (similar to current stable version of Outlook and most other email clients). Currently in "New" Outlook, when attachments are saved, saved, they have read-only permissions.

When I'm using more than one monitor and authoring a new email on the second monitor, the dropdown menu for quickly adding recently used email addresses (in the "To:" field) needs to display on the second monitor, as opposed to the primary monitor.

Right now all the panes are quite large. Right now I pretty much have to use Outlook full screen if I want to get the folder list, message list, message body, and My Day all on the screen without having to do a ton of scrolling left and right on the message. Not sure if this should be fixed with the ability to change the font size in the folder list, auto-resize the calendar widget as we shrink the column size, a combination of those, something.

I would like to turn off confirmation when deleting from Junk folder. There does not seem to be a setting for it.

Option to make it permanent. Why does it go away?
It's a pain to have to enable this every time I want to look at junk messages. Should behave as the other folders.

It would be interesting when creating an appointment with participants to have the next common free slot as a suggestion