I wonder if there isn't [one] use-case that many of the "slim" phone manufacturers are forgetting when testing their new buttons.
I'm originally from Los Angles, so 90% of my mobile phone usage took place while driving my car. It is almost impossible to "touch-type" a number or even speed dial a number on a Razr, Samsung T519, or HTC Wizard. After watching Steve Jobs use the new iPhone during the presentation, I think it will be just as, if not more, difficult to use the iPhone in a "touch-type" scenario.
Which isn't an issue in Australia; the United Kingdom; Ireland; Japan; Germany; Spain; Singapore and at least twenty-one other countries which have passed laws making it illegal to use a mobile phone while driving.
Moreover, according to the Governers Highway Safety Association, within the US
Connecticut, New York, New Jersey and the District of Columbia have enacted jurisdiction-wide bans on driving while talking on handheld cell phones
And California will join this group in July 2008.
I don't know the outcome, but back in July 2006, the Kansas State Legislature was considering a bill to ban all mobile phone use while driving, even hands-free use.
Given how dangerous simultaneously driving and using even a hands-free mobile appear to be, the Kansas Legislature may have been on the right track.
FWIW, I don't have much of a problem with the laws against it, and I don't have a problem if it turns out the iPhone's design makes it 'almost impossible to "touch-type" a number or even speed dial a number'.
Discouraging such activity seems a positively good idea, in fact.
Heading this back towards user-interface discussion, our desire to use a mobile while driving whilst not being actually competent to do so appears to be a specific case of the more general point: humans have a more limited ability to multi-task than we like to admit, even to ourselves.
So, would user interfaces be improved by acknowledging our general unwillingness to accept our multi-tasking limits and catering to it?
'Save Changes?' alert boxes -- especially ones where the default action is to Save when the Return key is hit -- which appear when you try and close a 'dirty' document could be seen as early examples of being forgiving in the face of our tendency to try and do too much at once.
OTOH, would we do more to improve interfaces by designing specifically for our strengths and assume people interacting with our tools are primarily concerned with the job at hand?
Or should we be looking to get some of the interactions out of the visual and into other sensory input streams, given that's apparently a way in which humans do show a capacity to handle multiple inputs?
Finally, does catering to our multi-tasking weaknesses end up, inevitably, causing conflict with the value created by catering to our strengths?
For example, I've lately discovered I'm more productive at the keyboard when using WriteRoom in full-screen mode compared to Eudora or even BBEdit, my two main writing tools for the past decade and more. But, to achieve this productivity, I'm giving up all the interactivity and capability of Mac OS X's unixy goodness, working in an environment not too far removed from WordStar 3.0 for DOS.
Against that, WriteRoom is only a more productive environment for me for certain sorts of writing. This post, for example, was written in BBEdit 8.6, with its new and quite nifty syntax colouring support for John Gruber's Markdown; checked in BBEdit's Preview as well as Safari, Firefox and other browsers; and posted here using Brent Simmons's (now Daniel Jalkut's) MarsEdit.
Without being able to bounce from BBEdit to Safari to Firefox to Eudora (to check the original post and see if any replies made this whole exercise redundant) to MarsEdit and elsewhere while putting this together it never would have been started, let alone finished.
(It's an arguable point if getting this finished is a good thing, of course. If you've read this far, however, I've at least managed to distract you for a while. Job one, at least, is done.)