Tab does not work on first word in row.
Super and subscript should work on any character not only predefined 2 3!
Text needs to be justified left center right AND to paragraph which is still missing.
this is actively being worked on by @alain, and you should see this in an upcoming WIP build soon:
In my daily build Super- and SubScript work for other characters and Tab indents are working also for the first words.
If you are referring to fully justified this is on the list as
RH-24598 Full justification for text
and marked for 9.0
thank you. so it seems it is fully handled then. i am glad 
@Alain good luck. deliver the best you can!