Anyone who is interested, much of this classic has yet to be tried properly afaik: https://en.wikipedia.org/wiki/The_Humane_Interface
Another idea: instead of having Photoshop/Excel etc. clones, have a document centric rather than application centric UI and allow features to be installable when they are needed (micro-apps?). E.g. Gaussian blur or spellchecking could be things you’d add from a microapp directory which would add an extra button to your interface for images and documents respectively.. you’ll build up a personalised interface and ‘own’ it, rather than being presented with a sea of unknown buttons/menu-items.