Apple has a tendency to ignore what's best for a select niche, and do what's best for all people. They have an odd way of prioritizing new features, ensuring they are the ones who come out on top. Portrait keyboard probably is best as it gets testers out there to make sure the thing is really finely tweaked. But landscape keyboard should defnitely still be availabe across all apps, for sure!!!
Apple has a tendency to ignore EASY things to correct, with the iPhone:
(1) landscape keyboard
(2) copy & paste (i could think of a number of ways to do this, but they'd prolly rather you pay extra for a C&P add-on)
(3) SMS
(4) bluetooth profiles (why pay for millions of bluetooth chips if you're not gonna give the chips functionality to work with stereo headsets & external keyboards & such... majorly sucks!!)
All of these issues are software related & Apple knew about all of them from day one, but they ignored them because they think "their way" is right.... just like how Macs still don't have a right-click button. I would have bought a MacBook and 32GB iPod Touch last week, but oh wait... MacBooks still only have one button.
The stubbornness of Apple is still persistent, and for what reason?? To sell more apps in their new App Store?? I don't think they really listen to customers that much. How many people can you count on your fingers that wanted a "landscape calculator". I counted ZERO!