Iphone upgrades, standard practise?

Apple had announced the new Iphone to be Iphone 4s. It is considered as an upgrade version of the Iphone 4. The upgrade isn't just minor. It got improved camera, voice commands, and a better screen. Maybe after ever new model there should be an upgrade model, like Iphone 3, Iphone 3GS. With all the negative news of a stolen prototype Iphone 5, fake iPhone 5 floating around, it should be a good time to redesign the new iPhone 5.