I'm not near the expert on all the scale/differences/etc., but it looks like a new/different AT-AT to me as well. I know that I'll likely pick up one, probably at full price unless it is incredibly disappointed. It would be neat to have a few, but I just don't have the room (or budget) for that. It was said earlier in this thread I believe, but after getting the recent AT-ST (not to mention the AT-TE and Falcon), but those really made that POTF2 AT-AT look "old". As long as it is a fair amount larger than the previous version, and has some nice features, I think I'd be happy.
It was mentioned over on RS today that this will likely come out in the new "CW" theme packaging. Not that I expected anything different, but I was just thinking how neat it would be if we got things like this and the new Snowspeeder/Cloud Car in vintage packaging as well. I know all of those will likely see the blue CW themed stuff, just like in the past, but it would be cool if they used that vintage-type packaging (similar to the VOTC/VTSC and upcoming "vintage" line) on the non-CW stuff like this as well.