>Proper integration with the notification center of Windows 10 (not the popups that are not integrated).
I'm not following this one. You have the choice, depending on how you have Outlook set in Settings/Apps, for whether the toast notifications accrue in the notification center. What else could "proper" mean? I leave that setting off, because I don't want them stacking up there, but you have the choice.
>Move to proper UWP or modern infrastructure so we don't have to restart the application if we have multiple monitors of different resolutions.
Please dear god no. Solve that another way, a truly "proper" way, which UWP most certainly is not. Outlook is faaaar too complex of a program to be put through that sieve. MS couldn't even translate Skype(!) properly to a modern infrastructure, so something with a ton more to it like Outlook stands no chance. If they tried, they'd get a toy app like Mail that comes with Win10, and that would be the end of Outlook. UWP just doesn't support complex things--not even something simple as a tray icon.