Work in Progress

  Did something like sudo apt remove ubuntu-desktop
  sudo apt autoremove
  And then the stuff above to install the UBuntu MATE meta packages.

  Proper way to install the Ubuntu MATE desktop meta packages is:
  sudo apt-get install ubuntu-mate-core^
  sudo apt-get install ubuntu-mate-desktop^
  And you will absolutely want to add the Fresh MATE mate PPA, since it includes loads of bugs fixes that have not made it to the archive.
  sudo apt-add-repository ppa:ubuntu-mate-dev/fresh-mate