Autocompletion is a nice feature that helps users to type words that occur often more quickly. While it sounds difficult to implement, VE actually makes this quite easy. I wrote a quick-and-dirty proof-of-concept user script: https://de.wikipedia.org/wiki/Benutzer:Schnark/js/veSuggestions.js Of course my script has bugs and limitations, but it shows the concept, and proves that this isn't as difficult as it might seem.
I think it would be great to implement such a feature directly in VE.