It would be great if the awesome delayed SMS feature was instead presented as an "undo" option. So the UI appears as if the text has sent, except with an Undo button, which disappears after the time limit as expired.

This changes the perception of the feature a bit (send-by-default with the option to undo kind of mindset), but more importantly allows the user to keep moving, perhaps firing off a few more texts (that would queue up).

Gmail does this with their Undo feature, and it's awesome.