Could be, but that doesn't really solve the problem imho - I want to be able to type a quick "OK" SMS one-handed while I walk down the street and hold an umbrella in the other hand, for example. Or skip to the next song. Or change the music's volume. Or read an incoming mail. Or...or...or...

With a phone, being able to do small things like that with one hand only is paramount to me, and with a like 95% landscape-only UI this is simply not possible.