I understand the comparisons between Azog and Lurtz, as they serve a similar role in each film. But for me the analogy doesn't work. Lurtz was simply giving a name to something that was already in the book -- the orcs who kill Boromir. For the sake of a cool visual and a dramatic fight scene, the movie gave the lead orc a name. As for "potato face," that was intended to be Gothmog, a character from the book. So again, it's adapting an existing aspect of Tolkien's story.

Azog is a different situation. He's taken from Tolkien lore, yes, but in way that contradicts what Tolkien wrote. His addition to the film doesn't expand on something that was already present. It adds a completely new element.

I think that's why I disliked Azog so much. His very presence is a reminder of my issues with an otherwise awesome movie. He contradicts Tolkien, he adds a new unnecessary element to the story, and he exists to give film 1 a strong villain, something that wouldn't have been needed if Jackson hadn't decided to do a trilogy.

To be honest, if they had left the Azog plotline the same but used Bolg as the lead antagonist, I probably would have been okay with it. I know that's nitpicky and silly but to me, it would have felt more organic to the Hobbit story. It would have expanded an aspect of the book, rather than insert a dead character from a completely different story.