On 3G: I'm assuming Apple can swing the same deals with carriers, essentially a pay-as-you-go per month, no contract needed. I think Apple should add 3G capability (and eventually 4G) on all of their devices, at least as an option, including iPads, iPods, MBA, and MBP. I definitely think the $130 price premium for the capability to by Internet access is worth it.
I could get an unlocked iPhone, but that's $600. If it was $300-$350, it would be quite a bit more attractive. If they come out an unlocked phone at that price, then great! But then again, an unlocked phone doesn't mean the pay-as-you-go plans will be there either. Apple or the carriers would have to step up.
On iPod touch display vs iPhone display: Yup the iPhone display is a lot better than the iPod touch even though they are at the same resolution. An IPS display (which the iPhone uses) is the best all-around type of display on the market: bright, high contrast, good blacks, low power, and awesome viewing angles. Perhaps the only negative is the slower refresh rates, but that doesn't appear to be a problem. And it is expensive. I don't know what the iPod touch display is, but it's very characteristic of TN displays with not very good viewing angles, but it is cheaper than IPS displays. Cheap is basically the only reason why the iPod touch has a lower quality display.
Maybe Apple has driven down the cost of the iPhone IPS display suitable for putting into iPod touches after having shipped, what 50m iPhone 4 devices. If so, an IPS display on the iPod touch 5 would be awesome.
On 128 GB: Flash densities are there to make a 64 GB SD card sized flash package, which is about the size of the flash package in iOS devices. I don't know why someone would say iOS couldn't handled it. It should handle 128 GB no problem.