Please get rid of the pop ups notifications and switch to the native macOS style notifications.

"View Source" was an important tool for looking at the source (headers, body, servers, etc.) of a received message. It was in the context menu (right-click) but is no longer there. I could not find it in the menus either.

When sending an incorrect email add the ability to recall that email from all recipients as is possible with Office for Windows client.

Ooops - did we lose the 'Resend' option for sent messages?

With the New Outlook for Mac, you seem to have removed the functionality to right-click on an email and set a reminder/flag/due date for a mail item. Can you please return this functionality? I found it especially useful for items that I could not act on at the moment but needed to follow back up with.

I know I can tap in open in new window, but having to press it everytime is tedious and prone to mistakes

There is no easy way to toggle the Sidebar, when extended/open, you need to go to the view menu but once collapsed/closed. there's a nice icon to extend it again.
This icon should always be visible to the user.

Add support for voting buttons.

Literally can't even use the new Outlook now since we rely on this

Skype integration into the meeting creation tab was one-click and easy to do.

Right now all sub-folders including sent items show up by default making it very long list for each email.

In Outlook for Windows I can add a send delay to every message as a rule. I like doing this because it gives me an extra minute or more to change my mind about an email after clicking 'Send'.

The web version offers a 10-second delay, which is even better than nothing.

It would be good to bring back the ability to resize columns in "New Outlook" since I'd like to see more of the message title and less of the sender.
It would also be good to be able to change the colum order, or move the delete/archive flag column back to the left. In the current order, I keep accidentally deleting messages, something I never did when that column was at the left.

The web based outlook.com and the windows version of outlook 2019 and 365 both support alias support. Only the mac version does not support this. It would be very useful if such support was added.

The "Send Availablity" feature is iOS is one of the most useful features I've ever used. I actually switch away from a desktop interface to the mobile version of Outlook just to use that feature. It is that great! It would be AWESOME if the Outlook for Mac team could bring that feature to the Mac Desktop client.

Encouragement... 🤛🏼

Currently, there seems to be a lot of 'dead' space in the new UI. While I like the more modern look, it should be possible to makt certain UI elements a bit more compact, much like is possible on Outlook for Windows...

I would love to be able to arrange my email accounts, like have them in the order I want instead of the automatic ordering from AtoZ.

Outlook for Web condenses the conversation nicely; expanding only the most recent message and giving a preview of the others. You can then expand each previous message separately if you need more context.

I LOVE the Outlook web app and want it as a native macOS app.