The Balrog should have been smaller

Well, if after ten hours of film the only complaint is that one of the beasties should have been smaller I guess they did alright.

I've seen many artist's paintings of the the battle on the Bridge of Khazad-dum made before PJ's adaptation, and there's a wide range of interpretations regarding the Balrog's size and appearance (and illustrating both sides of the wings debate). Some of them depict a Balrog even more massive than the one PJ envisioned.

In FotR, Tolkien only described the size of the Balrog with this line ..and suddenly it drew iteself up to a great height, In contrast, Gandalf is described as seeming ...small, and altogether alone: grey and bent, like a wizened tree before the onset of a storm. This vague and relative description of the Balrog lends itself to a wide variety of artistic interpretations.

The book said that the Balrog's wings spanned from wall to wall, and since the cavern they were in was reasonably large, I think it's safe to say that the Balrog was large as well.

JRR Tolkien vaguely described the Balrog as a man-shaped spirit of fire and shadow that could change size. I thought Peter Jackson's Balrog looked like a generic video game demon monster from "Warcraft". I thought Ralph Bakshi's Balrog was weirder and creepier.

"like a great shadow, in the middle of which was a dark form, of man-shape maybe, yet greater", which is how Tolkien described the Balrog, is closer to how Sauron appeared in Peter Jackson's "The Hobbit".

My biggest gripe is when they were talking about "Second Breakfast". There was never any mention of Second Breakfast in the books, so the movies from that point on are totally invalidated!

I mean, sure...mythologically-speaking, yeah, I'd agree with you. I picture the Balrog as made of shadows, smoke, and fire - but solid more or less - a being discernible, but barely, in shape. I think it has a shroud of darkness that might house wings, and I picture it more humanoid than the Jackson or Bakshi versions portrayed.

That said, Tolkien was vague in his description and the beast might have been "man-shaped" as in "humanoid", which might or might not apply to height. A cyclops in Greek myth might be 25-30 feet tall, but still could be considered "man-shaped". The Balrog might or might not have wings, and might have varying degrees of fire and shadows and whatnot. The whip and sword are clearly stated, but aside from those, it's artistic license time!

As for the film, I think Jackson needed a shorthand way to show the audience what kind of threat this creature was and couldn't count on the audience knowing the lore of Tolkien backwards and forwards. If a two metre high guy in spiky armour with smoke and fire around him showed up, people might think, "cool". If a two or three storey monster shows up with a skeletal-beast head and giant wings, people think, "uh-oh". And, thanks to the wings and fire and the exact inspiration on the head, they also think, "that's a demon from Hell," and that's what Jackson needed. He needed a big, firey climactic midpoint to make us believe that they were in t-r-o-u-b-l-e, and that's what he did.

So, from a lore stance, maybe not the best, most "accurate" portrait (even if that's a vaguery itself), but from a filmmaking perspective, I think he hit the nail more or less on the head.