Most of these changes are welcome improvements. However, there's one change in behavior we're seeing that I can't find listed above. When users are in SharePoint and click on a list (any list NOT set to use the "Classic" experience), it opens in the MS Lists app. This could be confusing to those who are accustomed to working in SharePoint. There are two ways "back" to the SharePoint interface (the site name/link above the list name in the top left corner and the "focus on content" button in the top right corner), but they aren't terribly obvious. It'd be great if there were a little tooltip (one of those teardrop shaped buttons used to point out new features or functions) that highlighted at least one of those to help orient people correctly.
Also, in the past, there was URL parameter that could be used to open any SharePoint-based list in the Lists app. Since that's now the default behavior, is there a corresponding parameter that could be added to a list URL to force it to open in the SharePoint experience?