The new walking animations look very very nice. I don't know what "interpolated" animations mean, but it must be good!
The units' feet seem to follow the ground more closely, as well.
Basically what was done in OTA was specify what part should move at what speed and for how long. Interpolation takes the start and finish locations of all parts and rounds them out according to the time since the animation started using some trig functions (start slow, speed up, end slow, like a sine wave).
No, not at all actually. :) The problem with the TA walking animations is that they are specified at direct-moves to specific places, but at a fairly low framerate. The fido for example only updates about 8 times per second which is clearly visible. Benito described it better in a lost post, but basically these direct movement calls gets translated to a "move at this speed for this long" calls instead.
Basically each animation 'frame' consists of a series of turn and move statements that control the position of the pieces followed by a sleep command. From the sleep command you know how long the frame lasts, so all you have to do is calculate the speed you have to turn or move at in order to reach the specified position from your current position. The result is that you can update all the positions on each rendered frame (e.g. at 75fps), without the restriction of your animation frame rate (8fps or whatever), so that it all looks smooth.