I don't think the new iPhone will be called the New iPhone. I think the change in iPad naming scheme has more to do with it being considered a computer, like an iMac or MacBook, while advertised as the new iMac etc they are still just called an iMac. The confusion with that naming scheme when it comes to iPhone and iPad is that they usually sell the old product at a cheaper price point next to the new product, which they don't do with their computers lines. This means that you will have an iPhone 4S sitting alongside the new iPhone, which I guess is okay. But then you have the issue when the new new iPhone comes out, what do you call the old new iPhone? Or for that matter the new new iPhone? I suppose you could call the old one the iPhone and the new one the new iPhone, but that seems pretty silly. They need a naming convention to differentiate their products that sit side by side, however it doesn't need a carryover name like they have used in the past, just a name to differentiate the low and high end models. So for example, you call them the iPhone and iPhone +, then when the + gets replaced it loses the + moniker and the new one gets the + and so on. At the same time they need to identify that the old model is now the base model, so it should be 'simplified' somehow, for example jamming iPhone 4 innards into a 3GS shell. A bit like the old MacBooks and MacBook Pro's, the high end gets a higher end casing, because that is the premium version.
So they need 2 models at each launch, a high end and a low end, the low end with carry over hardware, but in a low end case and then a high end with new hardware in a high end casing. With each iteration the low and high end have the same names like iPhone and iPhone +. This would eliminate naming confusion and adopt a similar convention to their other naming patterns.
At the moment their naming is all over the place and very un-Apple like.