I just had a thought re: the idea that some of the delay could be due to a software update...
Since the Kindle Touch has the pinch-to-zoom to change font sizes and the text reflows to adjust to the change - wouldn't it be grand if the delay with Sony was so that they could update their pinch-to-zoom so it does the same? That would make me happy. I just don't see much point to the zoom in feature otherwise.
Like I said, just a thought.