Exactly. It is not always the new technology which is the best.
I did not own a Newton myself, but I have had a chance to play with them irregularily over the years. Since it is not trying to squeeze a desktop metaphor in a PDA format, it is much easier to use. It more resembles a "Palmtop" than a "Desktop".
Some basic ideas for a new GUI:
* what is the Trash? It is derived from the desktop metaphor...
* what are Files? Derived from a desktop metaphor...
* what is Drag&Drop? Derived from a desktop metaphor...
* What is Copy/Cut&Paste? Derived from a desktop...
etc.
So, a "Palmtop" must resemble a note/scribblebook, an address/phonenumber book and a calendar... Plus be able to play games, music, videos. And communicate, i.e. Mail&Browser.
So, one should IMHO think about:
* replace "Desktop" with a continuous (endlessly scrolling) working sheet (where you draw a horizontal line to create a new working area, i.e. open a new document)
* replace Trash by a LRU buffer (i.e. long time not used things simply disappear - or you have to wipe them out explicitly)
* don't have "Files" and "Folders" but a "Bag of Things" with search filters and tabs (e.g. ABC-DEF, Today-Yesterday-LastWeek)
* replace Drag&Drop with Mark&Act
* same with cut&paste
Some thought about Files: internaly, the system could still store files in a folder hierarchy. And simply allow the user to define an editable attribute "Folder Path" for it without breaking the "Bag of things" view. My idea is looking like Spotlight on MacOS X. BTW: the first Sharp ROMs for the 5500 did go more in this direction.
And what about Windows? On a Desktop, windows are usually tied to an application and an application can open several to show different documents. So, why not simply arrange the windows of all applications in the endlessly scrolling "Palmtop"? And make them the full screen width (but arbitrary height as needed).
A new document/alert/helper window would simply appear at the bottom, scrolling the others upwards. If you want to switch between windows and view more recent, move the scrollbar. Closing a window with the x button would remove it from the arrangement. So, this all would more or less become the task of a window manager. And IMHO it would not even break the usual GUI APIs.
-- hns