The website MacStories just recently published a well though and detailed review about all the changes within iOS 11 and its successor iOS 10. It also highlights the major improvements for the iPad use.
There is likely something in it for everybody. Also users who already think they already know everything. So have a look! But bring some time … already the website did cut the review down into 25(!!) sections.
https://www.macstories.net/stories/ios-11-the-macstories-review/