I would see it a bit more general: Outlook is mostly useless as email client in general (not looking at the groupware functionality). Even with Exchange or other server types, many simple things do not work reliably and never get fixed. And the simplest things are impossible, e.g. displaying the full email address of a sender instead of the name only (to make it harder to spoof senders). I suspect 2016 is the 2nd-last version of Outlook to be released and from then on it will be browser-only. That said, IMAP support is "strange" and has always been - OL trusts its own .ps ort .ost file more than the server which circumvents the general idea of IMAP. If you need Outlook, avoid IMAP and if you need IMAP, avoid Outlook....
JC What version of Outlook are you using? I have "2016 (16.0.9029.2016) 32-bit installed and it does not exhibit the problems that you allege it does?
Have you ever tried any of the MS Forums? Yes, I have and my customer uses Outlook 2016, current version. Without deviating too much from the topic of this list, I can/must affirm that the current OL is not a very good IMAP client. Also, if you have a way to get the email address displayed by default, I and many others would appreciate to hear how. I think discussing the other pros and cons of Outlook is a bit off-topic for this list, but rest assured that during a larger migration project I have found many problems that others also had and that have not been addressed.
JC