I’m confused about this - I don’t have the new 10.5 iPad Pro but my 9.7” seems to full functionality. Did something change?
It doesn't matter what size iPad you are using, MS Office for iPad is far from being "full function". It does a great job of DISPLAYING MS Office documents and one can make basic modifications to them, but anything beyond that is just about impossible.Nothing has changed. Microsoft allows full function on devices 10" and below. Larger than that requires paying for the app or a subscription to O365.
Functionally, MS Office for iPad is essentially on par with iWork for iOS and Google Docs for iOS.