I think Clark should have been kept as a human supporting character, perhaps even the main female human protagonist, but someone else was better for the role of Galadriel. I don't really dislike her specifically, her acting and portrayal just seems somehow off and out of sync and almost forced in some ways. I think it is sad that people attack her (there was a video saying that she needed therapy after the backlash), but when you are trying to be the main character in a $250 million production by a major company, that role does come with very high expectations and qualifications.
I'm not sure who, perhaps that blond British actress from The Great Gatsby? Again, I liked Arwen and Tauriel and their actresses immensely, they both seemed uniquely elven and realistic in a way that this young Galadriel isn't, really immersing you in an otherworldly setting with their performance and dialogue and interactions with fellow characters. I think the Eowyn actress, were she 20 years younger, could have made a very fine young Galadriel!