Backspace, often used rarely considered. As keyboards replaced cursive, backspace replaced erasers and whiteout. Then touchscreen keyboards emerged, yet backspace remained unquestioned and unchanged.
On a touchscreen, backspace functions as it does on physical keyboards, as if there were a real key with a pressure pad underneath. Then and now, backspace has a very binary 2-bit input: you can TAP or HOLD.
TAP and you delete one character at a time, it gives you control and precision over what you delete. But this requires an exorbitant amount of taps. Tap tap tap tap tap tap.
HOLD and you can delete many characters at a time, faster and quicker, with no taps. But you feel less control and it is easy to overshoot.
Both options, TAP and HOLD have trade offs that make them un-intuitive ways to remove unwanted characters. Touch is a new technology, the binary inputs of tap and hold are constraints of an old technology, physical keys — not touch. With touch, input can be much less binary and the way backspace functions can be rethought. This new technology allows a third input to come into play: DRAG
Drag gives the precision and control of tap with the speed of hold. All the benefits with none of the trade offs.
Each row of keys on the keyboard could correspond to lines of text in the entry field. Horizontally you can select a part of, or whole row of text. Vertically you can select multiple rows at once. Control, speed and precision are all increased.
Note: I designed this and drafted the post in August 2014, pre-3D touch — Apple have since introduced a cool way to highlight text.