Typing Japanese directly on a phone's numpad should be a huge pain, but the phones have for years featured very intelligent prediction that makes it so you can type much faster than English even though there are five letters per key (as opposed to three in English). The phones come with standard "dictionaries" and also learn your own patterns, so you rarely ever have to actually type more than one letter of a word. Based on the rest of the sentence, there are really only a few options of what could come next and the phone can figure it out from one letter.
Whenever I'm typing on the iPhone and end up with crap like, "Okay, then ill send you the file," I can't understand how something like this is acceptable in 2010. There is absolutely no reason the iPhone shouldn't know what I'm trying to type; even a simple grammar checker could solve this problem. A more sophisticated prediction algorithm could drastically speed up typing on the iPhone without changing the interface at all. If nothing else, at least stop making me type apostrophes.
I really hope Apple sees the vulerability in their aging keyboard and buys someone like 8pen or Swype so they don't fall way behind.
I can't see Apple going the route of Swype or 8pen, too confusing. Apple likes simplicity (how many decades before they succumbed and released a two button mouse?)
This device, based on my intuition, would probably offer significant increases in wpm, and definitely increase accuracy significantly.
It's not a question of being genuinely happy or not- if something better comes along, than obviously it should be adopted.