I'm hoping they'll drop numbers and have only 2 models: The iPhone C and the iPhone S.
iPhone C: 8GB $49, 16GB $99, 32GB $149
iPhone S: 16GB $199, 32GB $249 64GB $349
The iPhone C will, rather than be last year's model in a plastic shell, but would contain the same processor at a slower clock speed, or alternatively, the C model has, say the A8, while the S model has the A8X. The C model would also have only 1/2 the memory the S model has, and last year's S model's camera. New features would be reserved for the S model and would appear in the next generation C model. Other than that, the differences would be minimal.
In addition to the current colors, the C models would also come in Midnight Purple, Sunset Orange, Carbon Black, and Space Grey. The S models would appear in Space Grey, Gold, White, and Carbon, a new completely black model.
The iPhone C would be available on all major carriers as well as unlocked and all prepaid carriers and smaller, regional carriers, while the iPhone S would be available only through nationwide carriers, regional carriers, or unlocked.
The new iPhone C and iPhone S. Loving them is easy, that's why so many people do.