Make it possible to add any smart folder to the new Favorites in Outlook.

The quick access toolbar and the ribbon bar need to be configurable.
They contain buttons which are never used (e. g. "Print" – who prints out emails?!) or buttons are inconveniently placed.

MailTips: https://technet.microsoft.com/en-us/library/jj649091%28v=exchg.150%29.aspx
Policy Tips: https://technet.microsoft.com/en-ca/library/jj150512%28v=exchg.150%29.aspx

Please offer the ability to pin calendars for Mac clients similar to the Windows feature. Having to continually switch views is painful and is a step back from the previous version of Outlook that had the My Day feature.

Remove the incredibly annoying 'stars' next to folders as everyone I know keeps clicking them by mistake.

Unread folder (just like windows version), not a smart folder at the bottom of the list. I have 80-100 subfolders and many, many rules for my incoming email. Having the Unread folder at the top just like the windows version would be much more helpful.
Or, if not possible have the Smart folder option also be a Favorite.
Please at the Favorite star to Smart Folders too.

The new updates have removed the ability to drag and drop attachments from emails. The windows version still has this. I should be able to drag an attachment to another email without downloading it or drag and drop the attachment to the desktop.

Larger organizations with either "self-hosted" or Office 365 service using SharePoint as their primary source to manage and share internal information are currently unable to approve SharePoint workflows using Outlook 2016 for Mac.

Please enable Outlook for Mac to Approve SharePoint Workflows.

Bring back unified subfolders (Junk Mail specifically). Office 365 is WAY too aggressive when it comes to marking mail as Junk (everything from GoDaddy is moved to Junk, for example), and with me having 3 email accounts it's a PITA to continually have to check three separate folders. It was much easier when it was just one folder.

I regularly need to view multiple shared calendars (often 8 or 9). This is fine in Outlook for Windows which allows multiple shared calendars to be displayed side-by-side in the day view, but the Mac version limits me to 3 calendars side-by-side. Adding any more merges the content making it much more difficult to identify individuals and schedule activities. I'd like to see the restriction removed to allow multiple calendars to be displayed in individual columns making scheduling across multiple individuals and rooms much easier.

The Outlook client should have a way of syncing the email signature from the cloud.

It is important to keep all signature synchronized between all clients, Outlook web, Outlook client, Outlook for mac, Outlook for iOS and so on.

The Exchange Transport Rule is not an ideal fit for this scenario.

Add attachment support for calendar items and tasks. Also it should be possible to easily create a new task or calendar item with an email as attachment.

Outlook for Mac is not able to send out email as (or on-behalf) a Distribution Group, and always got error message with meaningless error code. However, Outlook for Windows is able to use a Distribution Group as the "From" to send out email long long time ago. This is a very important function for a team who facing users, for example Customer-Support Team or Operation Team.

Display multiple timezones on the calendar view, this feature is supported for Outlook for Windows and I really miss it. Having teams split between GMT and PST its a really handy way to schedule joint sessions.

Please add Quick Steps to MS Outlook 2016 for Mac. It's very useful to save time on repeated actions and common tasks for the work day.

Need the ability to assign tasks to others

As I'm getting older I find it harder to distinguish between very slight differences in contrast and hard to see very light text on light colored background. Please add a high contrast theme to Outlook. The new theme would be especially helpful on the folder list. Best would be capability to have purely black background with white letters or the reverse, white background with black letters. The current white background with light grey letters is killing my eyes.

It's extremely important to sync Calendar App with Outlook calendar to let me use Outlook for Mac instead of Mail App.

please add dark theme, it is one of the endless list of features that I miss since using Mac.