I was a long time Android user and I can see what you're saying, but to me, most of those differences don't matter. I've heard people say that the Outlook app on Android was much better, but I had some very poor experiences with it. After a few weeks I would have to re sync the settings to repair the connection to the Exchange account. If I didn't, I wouldn't get notifications until hours later, if at all. The app looked nice, but it's very hard to compare and contrast when W10M and Android L/M are completely different OSes with completely different design ideas. The Office apps don't seem to too different at all. I'll give the edge to W10M because they integrate better with the OS. Cortana may look slightly cleaner on Android, but it's features are much more limited compared to W10M.
Those are all just my opinions, but I have never seen a major difference aside from the Outlook UI when it comes to those apps.
EDIT: The Outlook contact and Calendar syncs on Android were very poor. At least initially I had to add my Exchange account to Gmail to get the contacts and Calendar to sync with Google's contact and Calendar apps. This may have gotten better, but that is borderline unacceptable in my opinion.