It's interesting... A couple points.
First, the shot of the film prop walking shows how significant a difference in height the walker has when it's walking. Notice the hip joints raise the "body" of it up by a bit. Compared with the toy, the propotions of the cockpit to the model seem accurate, as do the legs and feet. The compressed height of the toy can be attributed to the walker being in an "at ease" stance, making it appear short, but in reality it's not.
The small cockpit image from the slide is interesting as well... I compared it some with the Incredible Cross Sections when I got home tonight. I'm having some graphics issues with my PC, so I'm not 100% on this but the toy AT-ST's cockpit is truncated from the back of the seat to the rear. There IS space in a "real" AT-ST for 2 passengers as we saw in the films. There's no seating though, it's more just room behind the seats incase you must use it. Anyway, the cockpit is NOT using a significant bit of space behind the seats. I'm not sure why that would be, probably a design issue with the toy, but it makes the cockpit slightly inaccurate (or maybe there's more armor plating back there now?

), as the film cockpit had room for people. It's very cramped though. The ICS matches up fairly well to the cockpit details, for the most part. There's some creative liberty on the part of Hasbro, but the overall dimensions inside appear correct.
For the most part the outside details match up to the film model fairly well... The viewports seem sized right, the hand rail around the command hatch, the command hatch itself, etc., etc.
I'd say the vehicle is pretty spot-on, just eyeballing it. The real tell-tale is packaged shot, with a figure though. The figure's raised in the packaging to be more visible, while the walker's height isn't fully extended upward as well. It's significantly taller than the figure then. i'd say the picture with the figure standing next to it, has the figure photoshopped into the image, not photographed with the walker. The packaging image seems to imply that anyway.
I'm liking this a lot more right now. I had my skeptical views at first. I'm now very intrigued.
As deco goes, what we've seen from Hasbro thus far is attrocious.

Deco's usually the last thing I gripe on, on vehicles (figures I find it more important). On vehicles I can usually fix it. It's nowhere near a movie prop though. It needs a SERIOUS blackwash, as all the AT-ST's on Endor had the black wash look "runny grease/oil" looking stains.
Also blast marks, of which this toy appears to have none while the Endor AT-ST's all had one here or there, usually on front armor plating.