^ This.
This didn't work with unlocking the GS3 bootloader and this will be the same thing. This also wouldn't work for many other reasons, mainly financial and production reasons. If they go back to make a whole new device basically just for expanded memory they would have to replace an internal component, yes its small but you have to account for the labor, overhead and production costs of not just 1 device but 2 seperate or even 3 if you want to do a 16, 32 and 64.
A petition to unlock a bootloader sure, that is a simple fix where they just send out an OTA if they please but something like this will never work. And someone mentioned it before, the 16gb will be fine for MOST people. I want to highlight the most part. No company on the planet will be able to please 100% of their users. Therefore, you have to please the majority of their users which the 16gb will considering you can pop in a MicroSD card. I have a 64gb microSD card that I got on sale for $40 and couldn't be happier.
The only reason why Apple comes out with 16,32 and 64 varients are simply because they don't have an sd card slot (and because they want to kill your wallet). Be happy that Samsung gave you the option to add an sdcard. Could be worse, could be like the DNA or an iPhone where you get the internal memory and thats it.