More likely modeling a two legged wyvern was cheaper and more "trendy" according to somebody not interested in the book content, or the author's own pictures.
Benedict's performance gave a serpent-like appearance to Smaug and so the designers adjusted him to fit the way he was portrayed.
I thought he did the voice acting, are they suggesting he was doing the physical part as well ?(visions of him prancing around in front of a green screen being snake-like....)
Smaug was a big bad-ass Dragon bad guy. I always saw him more like an overgrown cat with wings!
sleepy when necessary - wide awake, fast, agile and a complete bastard when needed. I actually did not even realise they chopped his wings off and put flaps on his legs instead in the films sigh, shows how much attention I was really paying.
Makes him more like a fur-less giant flying squirrel really... A really nasty one.
Still that model is a brilliant one though a bit outside my budget.