The above post is a succinct summary! I would also add:
6) Done nothing to properly address the rather ridiculous situation of needing a full Exhcange server to sensibly manage Exchange Online mailboxes attached to hybrid accounts. Yes, I know it is now technically possible to remove the Exchange server, but that then makes a lot of tasks far more complicated than they need to be - escpecially simple tasks affecting one account which can be accomplished in seconds using the Exchange GUI. Seriously, how hard would it be to create a simple GUI-based management program to install on a local server? The underlying Powershell functionality mostly already exists so the GUI can just use that (using Powershell directly is of course possible, and efficient for bulk changes - but it's overkill for a basic change to a single account).