The current and previous Sony Reader models all had 2 card slots, so that microSD card slot is a major change. It suggests that this will be a major hardware revision -the one that ereader advocates have been pining for for the last year or more. It could even put Sony ahead of the competition, depending on what it can do.
Next, the name. Did you catch the significance of the model name? This is the PRS-T1, and all previous Sony Readers had model numbers. The T might stand for tablet, which would suggest that it won't have an E-ink screen. But the T1 label might also mean that it's using the same naming convention as the S1, S2 Android tablets. Those are code names, not model names, so the T1 might not be the final name of this ebook reader.
Given that this is probably a major hardware revision, we could be looking at a Mirasol ebook reader. Yeah, yeah, I have an obsession with figuring out which ebook reader maker is working with the Mirasol screen. But that screen has to show up somewhere.
No press event scheduled
I thought it worth noting that Sony haven't scheduled the launch event for the new Sony Reader. I have been gently bothering the Sony Reader rep for a while now, and I have not gotten even a hint that an event was planned. Even though I believe that a new device is coming, the only definitive sign of its imminent arrival is when Sony throw a press event. Until then the device is little more than a myth.