"Did a good job" is a comparison to expectations. She was not expecting to be subbing for Pat Sajak that day, nobody was. He got sick overnight and needed to be hospitalized, and there was a taping schedule the next day that would have been a nightmare to cancel. She was asked to step in, and the first taping or two was ragged (as any reasonable person could have expected), but she improved enough to be kept on as substitute host until Sajak was able to return. Now that she's a known entity in that role, making her the short-term host and gently introducing the long-term replacement would avoid the "Never Replace a Legend, Replace the Replacement" problem.