I somehow think if every key were to implement this, then quick typing would quickly lead to troubles. Why not simply do a long press for most punctuation and s

I somehow think if every key were to implement this, then quick typing would quickly lead to troubles. Why not simply do a long press for most punctuation and show it underneath, as on Android? I used to hate this about my iPod Touch, which I did a lot of typing on (often used for IM) and I am already faster using the touchscreen on my Android phone then I ever was on my much-used iPod (after 2 weeks with the phone and a year with the iPod). That said, I doubt this is a independent-developer possibility. Alternative keyboards for iOS have, thus far, been limited to their own app, such as ShapeWriter as there is no way to implement them system-wide.. you can copy and paste and what not, but it's far from convenient.