Ever have a discussion between somebody where you described something of crucial importance to you and had them shrug their shoulders back at you?
I'm realizing that, as far as phone input goes, it's kind of like that. As far as I can tell, either you care, vehemently, about having the fastest possible text input for the size, or you don't care about the input device at all.
I'm very textually oriented. I see my phone as a tiny computer that happens to double as a phone. I'll blog from it, send emails, etc. I've never been totally comfortable with on-screen input, even when I've given it an honest try. I've used handwriting recognition, graffiti, stylus-keyboards, iPhone keyboards, etc. I just like the keypad much much more.
While keyboarded phones are fairly popular, not everybody is like me. As time as gone on and I've talked to more and more people about their devices, I've realized this is an either-or. The essential genius of the iPhone design is that, if you don't like a full fledged keyboard, you also don't care about a keypad or even the presence of more than one or two buttons. Thus, if you need a keyboard, you can pop up the onscreen keyboard. If you just need a numeric keypad to dial, you will have an easier time with one that's on-screen instead of one integrated into the keyboard layout.
I think this is interesting, because I'd not have thought it to be the case until recently.
But I suspect, in the long-term, we will cease to see devices that do things half-way. Consider that every time somebody goes halfway and just adds a numeric keypad, the next version either turns it into a full keyboard or does away with it entirely. The touchscreen-less Windows Smartphones went that way. Nokia's N-series lineup went that way. Nobody cloned the Pantech Duo design.
I wrote a draft of this post before I got an iPad. My biggest observation after I've got an iPad is that my typing speed and comfort with the iPad is about the same as my Droid and that both are faster than an iPod-styled keyboard.