If you're going to remove OneNote from Office 2019 and recommend people use the less full featured OneNote UWP app...you need to add pageTemplates from OneNote 2016/365 to the UWP app.

All functionality for Page Templates,
Creating a template
Saving a template
Using a Template as default for a note section

It would be really helpful if you could rotate inserted PDFs in OneNote. Currently, the "Rotate" button is grayed out.

One of the most powerful feature is the ability to tag things as Outlook Tasks. Also the ability to create a OneNote page from a meeting. These features are the heart and soul of OneNote.

For all the OneNote desktop user since the beginning.
It is important that all the local OneNote-files can be used in the future without an upload to OneDrive.

Please add page sizes so we have the option for the pages to look like microsoft word in a way but in one note so that i know how much i can fit in one page in order to print it out and study from my notes

By default there is no way to see if your written notes exceed one page. You have to write very small or adjust the whole text to fit into a page so I can print it out.
I would appreciate a feature like in Excel where you simply can tick a box an you can see where the border of a page is.

I really like the desktop lay-out with notebooks on the left, sections on top and pages on the right. I tried the UWP version, and while perfectly suited for use on a tablet (with a reduced number of - bigger - buttons), I feel it misses too many features to replace the desktop version.

So please include OneNote in the new Office 2019 suite!

Outlook allows me to "copy" an e-mail via "Send to OneNote" into a page. This is only working with the OneNote 2016 desktop app. It would be great if I could send an e-mail to the UWP OneNote app.

Integrate tasks and tags across OneNote, Outlook (desktop/web/app), Windows 10 mail/cal, and Microdoft To-Do app.

Customizable tags is a feature my business can NOT live without. This is the only thing that keeps us from switching to OneNote (from OneNote 2016)

1. I'd like existing OneNote 2016 & 2010 feature "Insert Outlook Task" be included in OneNote for Windows 10
2. I'd like OneNote Linked tasks be available at my Android mobile device.

In the Microsoft Store version of OneNote, when I click on a link to a file stored on my PC, I get the message "Sorry, we couldn't open the notes you were looking for. They may have been moved or deleted or you may not have permission to open them."
Links to files work fine in OneNote 2016. Please make them work in the Store version.

Need to continue to have all Outlook integration functionality in Onenote for Windows (particularly task creation) if you are going to sunset Outlook 2016. Difficult to understand how it could be a good business decision to do otherwise.

The ability to export single pages, sections and entire notebooks into a pdf file is a really helpful tool, that is missed by many users.
See also:
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_onenote-mso_win10-mso_2016/how-do-you-export-a-pdf-in-onenote-for-windows-10/371daf74-9084-4d84-a806-8ea6bb93935a

Please include this into the windows 10 version!

The infinite paper size being the only option forces me to keep using OneNote 2016 or a simple pdf editor instead of OneNote for Windows 10. It is impossible to export anything from OneNote if I cannot tell where the page ends--it always will format horribly.

I would like the video recording feature to be returned! I need to be able to continue recording videos into my OneNote. Not linking---recording directly from OneNote.

I really like the quick note and screen clipping in OneNote 2016. Can you also made them in OneNote for Windows?

A 'store' for templates where people could post and search for templates to download.