This is the same way that the SGS2 was released 2 years ago. Afair, ATT never had other than the 16 GB SGS3. When the SGS3 was announced, the 64 GB model was stipulated to come later - and it was much later lol.
With 2 motherboards/processors and all of the radio variations, starting with a single storage model seems more like a typical Samsung release than the SGS3 was.
The pent-up demand from SGS and SGS2 upgraders is probably going to move the 16 GB version as quickly as they can stock them.
I don't know if rushed to market is the right term, or yeah, maybe it is. But it wouldn't help them to wait in the face of this year's competition. This year the new Samsung is just not eclipsing everything else in the press by any means.
As for reps telling people that apps can go on the sd card, meh, they've been saying that to people for three years.
That's why we're here, so people can get the facts.