In no uncertain terms let me state that the experience of watching this movie was something akin to watching somebody else play a video game for two hours. (Read: not awesome). That being said I came into it without any high expectations, any hope I had for the hobbit movies had been thoroughly dissipated by the first and second ones… A real shame considering my love of the book. My specific expectations were set by Peter Jackson's approach to the Return of the King which, not dissimilarily, was essentially one long drawnout battle montage. While the experience is fresh in my mind though I do want to write down the moments of battle terrain dynamism that I think could inform a more interesting tabletop experience. I say this as a non-video gamer, I'm sure that those who partake in video games have enough inspiration from that genre.
General use of tactical positions: Raven Hill, front door to Erabor,
Note to self, set points in the map of story rich value.
Changing terrain: falling tower, cracking ice,
Think about how things can change and build it into the description e.g. "the granite pillars seem to lean ever so slightly, drawing your attention to the eroded bases".
Highjacking: flying opponents, mobile siege equipment, giant/gargantuan opponents.
Make sure to point out these opportunities to players who are not fully engaging in creative tactics E.g. "a successful acrobatics check will allow you to hitch a ride on the back of the giant serpents head..."