I tend to agree. The iphone is a device with lots of functionality, all competing over the same resources(and that includes price, in a way). So for instance, it's battery will be used by all the standard phone things, as well as gaming, leaving less overall for both. Additionally, they wouldn't make buttons that you can feel, because it would take away from the phone's needs (ie. it would make it larger, more of a brick), even though they're useful for games.
Then think of the purpose behind the DS's dual screens. The idea is that you have a screen that your hand doesn't cover while you're using the touch-screen for input. The iPhone is never going to be able to follow that kind of philosophy. In other words it has values that limit it from adopting values necessary for gaming. On the other hand there's nothing preventing Nintendo from using the developments the iPhone has made in their next handheld, we could easily see a multi-touch screen, accelerometer, and wireless network functionality (which, rather than always being on only turns on when it needs to). And unlike the Wii, I expect Nintendo will release a successor for the DS in the next couple of years.
The all-in-one device may be the future, but I think it's the end-game, not something that will work out now.
A game I'm developing with some friends:
www.xnagg.com/zombieasteroids/publish.htm
It is largely a technical exercise but feedback is appreciated.
