Ken Segall makes the case that the next iPhone should be called the iPhone 6, not the 5S:
The Apple designers tried their best with the product graphics, but there is an inescapable reality: 4S will never be as simple as 4.
More important, tacking an S onto the existing model number sends a rather weak message. It says that this is our “off-year” product, with only modest improvements.
Sound reasoning. Marco Arment chimes in:
Since they’re not going to meaningfully improve their PR momentum anytime soon, they might as well at least avoid trying to make it worse. This is not the time for Apple itself to suggest to the world that it’s slowing down innovation on its most important product.
It’s truly incredible how powerful a simple number can be. The significance of the S branding is that it reads as a perfunctory improvement, even if it’s a reasonable upgrade to everything except the case. But even if it’s branded as the iPhone 6, I think the press will still snidely call it the 5S if it’s in the same box. Look at their reaction to Samsung’s Galaxy S4.
John Siracusa thinks Apple can justify this rebranding if they introduce colours. I think multiple colours are unlikely — partially because they’ve been able to ship a multicoloured iPhone since the 3G and they haven’t, and partially because it significantly increases production complexity on a product for which Apple already struggles to meet demand — but it could be enough leverage for the perception of a full version number upgrade.