Reasonably long menus where necessary so that very common actions are still in the top level. But retain the principle that the previous menus were too long and that single submenus can be good.
Stronger features for those who need to import then export-overwrite hundreds or more files per day. Where the user is able to automate this, enhance Chains so that it actually supports all the formats that Audacity supports.
No-GUI command-line support so that e,g. effects or Chains could be run on files or on a list of files without slowing down to draw waveforms of the files.