Scoble explains the problem:

When showing my phone around I actually get a lot of questions about whether or not to go with a keyboard-style phone. Here’s why I don’t: I used to have a Blackberry (back when I worked at Fawcette) and I used it so much that my hands hurt. Really hurt. I lost my Blackberry in a cab in New Orleans and my pain went away. I realized then that it was the thumb keyboard that was causing my hands to hurt. Let’s face it, I was addicted to that thing (and this was before blogging, imagine if I could post from my phone!)

You can make the devices smaller, but the hands are still the same size. If it doesn't have at least a laptop sized keyboard, I'm just not interested - like Scoble, I'd be tempted straight into carpal tunnel syndrome.