In Kazadum where the steps break apart and they have to get across, the comp work isn't good at all, even if they are minatures. It's the same with the closeups of Merry and Pippin on Treebeard. When they go wide on Treebeard, he looks great just as the wide shots on Kazadum are great.
I like the Balrog too...even if you can't make out most of it. But, that's not a knock against it. I mean, they're in a dark environment so you can't change that. Still, I like the Balrog in The Fellowship.