I want to start off by saying that one of my most favourite scenes in the whole trilogy is when Frodo claims the Ring on Mount Doom. That one was very well done in terms of the acting, however shaky it was in other scenes. I suppose it's more credit to the costumes and lighting, though, but I still like it. If you just take this scene compared to the beginning, and ignore some things in between, you'd admire the change from
this to
this.
I do agree about the overall acting being weak. Frodo is supposed to show pain through courage and strength. In the movie all he shows is pain. Really whenever I imagine Frodo anywhere in between Shire and Mt. Doom, the expression on his face is invariably a variation of
th
is.
Don't get me started on sending Sam away!
I know they want to show that the Ring (and Stinker) are working on Frodo, but this is pushing the line just too far.
And Osgiliath too -- but I suppose I detest Faramir's portrayal/role in that part more than Frodo's, so I'll rant about that when we talk about Faramir.
I'm not so sure about the Frodo-Gollum relationship, but my memory is not very clear on that. When/if I watch the movie again I might be able to comment. The one thing I do remember is that there was a moment when Gollum comes soooooo close to repentance in the books - and it's just not there in the movies.