Indeed, such a boost in ergonomics and productivity with just a "simple" choice. Btw, I was always amazed by people breaking this functionality by insisting using other keyboard layouts, more appropriate for text.

Think you're right, it rings bell (albeit faint). Did the Wang wordprocessor use it too? (I used a Wang WP a few times long ago but I've no idea now. In fact the Wang was the very first WP I used — except for KP26/29 card punches with an IBM-360.) :-)

The Wang WP didn't use the Wordstar diamond. It used function keys heavily, copied later (or ported) by a program called Multimate to the IBM PC.

Yeah, on second thoughts I reckon you're right. The last time I used one was around '73 - '74 or so - so now it's all pretty vague. The few things that I can recall are that it was a large console model that used 8" floppy disks and editing was as slow as a wet week (writing to the floppy took a long time especially for a large document of around 50-100 pages).