If it IS a Target exclusive, then they'll probably be hush hush about it. If it's a general release item, they may be a little more forthcoming since word is out. I'm sure they'll say "Details at Toy Fair, you all will be pleasantly surprised.".....and then, we won't.
My guess on the size and "play" features.
It'll measure around 22" long and be about 8" wide, not counting the legs of course. There will be a canopy that lifts and holds 1 Driver (included). The body will be hinged just above each rear leg and clip in the middle on the top. There will be room to sit 3 Clones on each "bench" on either side. The guns on either side of the cockpit and chin guns will "ball rotate". The main cannon on top will rotate 360, and fire a projectile. There will be a seat that holds the AT-TE Tank Gunner figure (also included). The legs will be articulated at the "hip" and "knee" joints. There will be 2 more "ball rotating" guns on the rear. No sound effects, and the driver will look like the gunner without the pauldron, and have a farout paint scheme we'll most likely hope they rerelease as a "Legends" figure because it's so GD cool.
That's just my guess though....