Microsoft states that it has not tested delegate scenarios beyond a 1 to 4 ratio of delegate to managers, also known as the super-delegate scenario. Some guidance is provided on ways to handle super-delegate scenarios in this TechNet Blog post:

https://blogs.technet.microsoft.com/officeresourcekit/2012/12/17/recommendations-for-configuring-delegate-scenarios-in-outlook-2010/

Unfortunately, this post does not go far enough towards addressing a need to scale to larger delegate scenarios (think 1 to 40 or greater) and the performance hit to Outlook synchronization that is seen as the ratio increases.

In a super-delegate scenario, the delegate (or team of delegates) opening a manager’s mailbox will change day-to-day and as a result the Outlook sync takes a very long time to complete – sometimes minutes, sometimes hours depending on the last time a delegate may have last opened a specific manager's mailbox. As a result, the time to close incidents or requests by a manager to a delegate is prolonged and delays the ability to obtain business critical information. In some cases a delegate would need to follow-up sometime later with the manager after mail has synchronized.

Please consider addressing the need of Enterprise-level companies to leverage these larger super-delegate scenarios and the poor synchronization performance seen within the Outlook client as a result.

Icons in the Quick Access Toolbar (QAT) are now monochrome in Microsoft Outlook 2016. The custom icons which are colored are very limited in number. It would be nice to get Quick Access Toolbar icons in different colors.

Also, as someone with challenged vision, I find Outlook 2016 more difficult to see. I have had to turn on reading pane in order to zoom my emails so I can read them. But I really don’t like using reading pane. I have found a way to increase the font size in my emails list, which is helpful, but other than that, everything in Outlook looks too small (icons, calendar list, mailbox list, etc). I can find no way to enlarge these things a little bit so that I can look at them without straining my eyes. Please provide an easy way to customize Outlook appearance for people who are visually challenged.

Please don't block Windows shutdown if the setting to empty the "deleted items" folder on exit is set.

Do select a sensible default instead. Based on how autosave is behaving in other office applications, I'd say go ahead and delete without asking. Alternatively, skip the folder cleanup on shutdown and just exit. Whatever you do, just don't stop the shutdown sequence.

This is one of the most frustrating things in Outlook for me, as this usually happens just as I want to shut down the laptop and rush to the train station (this is also the reason I usually don't have time to send a feedback about it).

If you turn on AutoPreview in Outlook 2016 and the message list is in its wide mode, each message or conversation has about half a line of empty white space under each message's AutoPreview text.

I use 1-line AutoPreview, so this extra space steals over 10% of the available vertical space in the message list!

To repro:
1) while viewing inbox, turn off preview pane or move it to the bottom
2) maximize outlook so that it will switch to its "wide" mode with sender and subject on the same line
3) turn on auto-preview and set it to 1 line

Expected: message's bottom border is only a few pixels below the bottom of auto-preview text
Actual: half a line of wasted space.

There isn't any wasted space at the top of the message, only underneath it.

It doesn't show up when AutoPreview is turned off-- in that case, the display is very efficient without wasted space.