Feature Requests

Feature Requests and Suggestions has moved to techcommunity.microsoft.com.
This was launched in June 2021.

link - techcommunity.microsoft.com/t5/microsoft-365-developer-platform/idb-p/Microsoft365DeveloperPlatform/status-key/NewM365P/label-name/Office%20Add-ins%20development 
link - practical365.com/microsoft-decommits-user-voice/ 

Dialogs - Allow dialogs to be sized using pixels and not just percentages

link - techcommunity.microsoft.com/t5/microsoft-365-developer-platform/allow-dialogs-to-be-sized-using-pixels-and-not-just-percentages/idi-p/3043580 

Dialogs - Be able to customize the dialog title

Ribbon Commands - Invoke built-in ribbon commands from Javascript

link - techcommunity.microsoft.com/t5/microsoft-365-developer-platform/executemso-functionality-for-off
ice-js/idi-p/2993354 

Extend the "commands" to include built-in idMso for use in custom groups and tabs as well as repurposing
Support dynamic content in Ribbon dropdown menu

UserVoice (pre June 2021)

Microsoft did partner with a third-party service called UserVoice (in 2012) to communicate with customers and collect feature requests.
None of the old requests were migrated to the new techcommunity portal.
link - officespdev.uservoice.com (broken)