See https://support.microsoft.com/en-US/help/4010160

New calendar UX is very heavy. Visual weight is not really on appointments/meetings (i.e. what matters most), but on the surrounding UX elements. For example, black grid lines are too contrast and sticking out.

If google and apple have figured out this solution why is it so hard for Microsoft to do this

It would be helpful to see who has arranged an appointment in a shared calendar so any questions could be referred to the appointee.
This was a feature in earlier outlook versions!

When sending a contact as business card, and receiver opens it, the NOTES section does NOT SHOW UP. It would be great if the sender could see those details.

The "Mail" app is firmly anchored in the Cut and Sketch app. It would be great if Outlook were also anchored there or if you could address other installed programs such as Telegram or WhatsApp to share a screenshot.

When typing an email address on a new line, the AutoCorrect feature "start with capital" will replace the first letter by the a capital letter.

firstname. => Firstname.

An intelligent AutoCorrect could for example detect an e-mail-address and when continuing typing replaces the capital letter by a small one again.

1) firstname.lastname => Firstname.lastname
2) Firstname.lastname@domain.com => firstname.lastname@domain.com

This could be based on regex - or to reach most users probably better via suggestions, such as options. E.g. "Exception for email-addresses" and further functions for pros that are familiar with regex.

I wish there was an option for addressees/invitees on email and calendar items that was "For Your Awareness" rather than "cc" indicating they are not expected to respond or attend, but for those situations when they need to be aware....the optional and required options are not as explicit

Can you add the abililty to add julian dates at the bottom of the calendar.

Allow for different out of office/automatic replies based on sender's timezone - will be very useful when on business travel.
(Allow for "anyone NOT on selected timezone")

In LotusNotes, I was able to customize reoccurring meetings before sending them out. I have a monthly meeting that meets 2x a month on Wednesdays, but not always on the same Wednesdays. I was able to select which Wednesdays I wanted my meetings to fall. Then I would send it out to everyone.

When attaching a file to a message, if the file is open on the PC and has unsaved changes, Outlook should generate a warning message to remind the user to save the file prior to attaching it.

I use Outlook on a monitor in the portrait orientation. I would like to put the to-do bar on the bottom of the page.

enable an option to approval status invitation for all meeting participants (current only for Host is possible this visualization)

Add "Quick Step"/button that sends the current email to the last folder used to store the last email in that "conversation"/email chain.

It would be great if we had a way to "uncanel" a meeting request that was cancelled if you are the facilitator. Accidents do happen!

Include a report funtion in Tasks. This should include the ability to group tasks by any number of fields.

When scheduling a recurring meeting give an option to schedule it on a specific working day, ie working day 3 of every month. The current option only allows you to chose the 3rd of each month but this may fall on a weekend.