I read that Anakin does have new legs that have knee and ankles articulation. The battle droid has modified arms to grip the STAPs controls.
I found this today at Target (along with the Shield Generator Attack set, which I left sitting there) and can confirm that the Anakin figure has articulated knees and ankles, as well as a totally soft goods "skirt", making this the "ultimate" animated Anakin. The Battle Droid is a different shade of tan from the basic carded release, and the lower arms have been modified, as Jayson said, to hold the STAP controls, although the stress from the packaging and rubber bands make his legs prone to fall off. Mine are literally held to the torso by the blue electricity accessory, or otherwise, he'd be a legless droid.
The STAPs are the real winner of this set, though. I always liked the STAP as a toy, and the new CIS paint job looks great on these toys. Paying 20 bucks for two figures and two vehicles is well worth it, in my opinion, and it makes the Shield Generator set look like something of a rip-off to say the least.