Thanks for leaving us feedback on this!
Word Online is consistently working towards feature parity with our desktop applications, in addition to incorporating new features. Please let us know if there are any specific features you would like to see.Greer commented
The save needs to be seamless - when saving in Word online sometimes it reverts back to the original text and since it saved there is no way to get the few sentences/paragraph typed back and I have to retype it all. It is even worse when there are multiple people working in the file at one time - sections go missing. It is very frustrating.