I think if you still have a 3GS, you should bump to an iPhone 4. If you have an iPhone 4 I would stick with it til ver 6. I agree with what this report is saying. The faster processor and camera will most likely make it's way to the phone, but Apple will likely stop there and wait for a screen size improvement for a later version. Apple is not known for just upgrading all of a device's components at once. They tinker with a couple things and slap a new version number. It's what happened with the iPad2. Many expected a higher res screen, but that would have been too many component upgrades.
That's what I just did. The screen alone is worth the upgrade. I no longer feel bad about not necessarily getting the 5 and skipping that version and getting the 6 next year.