My list of needed software:
-A centralized preferences program where you can access each setting, and not a million icons in prefs like nowadays. Just like MorphOS or Pos (ProDad) do it.
-An icon editor that properly handles all Amiga icon formats (including PNG & OS4)
-A bugfixed new build of ScalOS
-A reverse engineered driver development kit for Picasso96 made publicly available.
-Some sort of Partition Magic for Amiga (That woul be indeed better than the aging HDToolBox)