of course it would be simple to implement in any old fashion. But you don't want to make it complicated for the user. Gestures can be abused. I see people talking about triple tapping the screen, using three fingers etc. Those are not elegant solutions.
We have to consider the gestures that are already in place...
- pinch
- double tap to zoom
- hold to zoom in with magnifying glass
- hold on link to show URL
- swipe to delete
- a bunch of gestures they may be playing with but haven't yet been implemented, yet still need to be considered
....and then implement cut/paste in that context. you don't want people to trigger one gesture when they wanted to do something else. I have enough trouble as it is putting a cursor in place in keyboard mode when there is a conflict between moving the page and placing the cursor.
The fact is that there is no established convention for mapping all desktop based commands over to a touch only interface. What Apple decides to do would effectively set in stone how it works going forward. So it HAS to be right.
I agree that it's difficult to do elegantly, although some of the proposed solutions I've read about are very clever.
But I'd settle for cut-and-paste only working it editable text fields, which opens up some other options. Four new buttons in the virtual keyboard - select, cut, copy, and paste - would let you perform those functions. For example, to select text, you'd position the cursor as you do now, tap select, drag to highlight text, then tap copy or cut. To paste, you'd position the cursor and tap paste.
You'd probably have to add a third keyboard "page," since there's little or no room on the alpha or numeric pages.
Admittedly not a gestures-only solution, but it would work.