I would think that adding more icons in the same screen size would be a little cluttered.
I found myself reading the orignial post in a southern accent because of all the reckons.
Why? Developers already have to develop for dynamic screen sizes on the desktop, they should be doing the same for the iPhone, and it should not at all be confusing. The only problem I see is if the screen size in pixels gets smaller, but I think that's extremely unlikely. Anyone developing with a fixed screen size in mind deserves what they get when it changes.