I can not claim any credit for coming up with the idea for this feature request – it just seemed such a no-brainer to me that I'm endorsing John Gruber's suggestion.
(For accessibility reasons, you can turn Shake to Undo off, but if you do, you do not have any undo at all. ) My best suggestion would be to take away some space from the auto-suggestion row above the keyboard and put in an undo button on the left, just like the iPad …
The screen – and therefore therefore keyboard – was tiny, so there was very little space to play with. It was not really practical to use some of that extremely valuable real estate for an Undo button.
The company came up with an innovative solution to this: shake-to-undo. Gruber says that the way he heard it, the idea actually began as a joke.
Here's an anecdote I heard years ago about how Shake to Undo came to be. Scott Forstall charged the iOS team with devising an interface for Undo – everyone knew the iPhone should have it, One engineer joked that they could just make make shake the iPhone to invoke it. Forstall said he loved the idea, and what was proposed as a joke has been with us as the Undo interface ever since.
The main drawback is that hardly anyone outside the tech world even knows that it exists – and I suspect that even many Apple fans may have forgotten all about it. I must say that I had.
Additionally, as Gruber adds, it can also be a little risky with today's larger phones. Sending your phone flying across the …