Newsfeeds are clogged with headlines and eulogies regarding Carrie Fisher's death.
Some performers make a film famous while some films make a performer famous. She became famous, not because she was a great actress, but because she acted in a famous film (or franchise). Neither she nor Hamill had the starpower to sustain a career–unlike Ford.
That said, making allowance for Lucas's juvenile sense of humor and cliche-ridden situations, I thought she was good in The New Hope. There's only so much you can do with the sophomoric dialogue.
She was miscast as a sex slave in Return of the Jedi. That's not something she can pull off. But then, that entire film was consistently abysmal.
I don't recall her in The Empire Strikes Back, but that's because it was mainly about Luke Skywalker's inward and outward odyssey.
I see many people praising her for mitigating the stigma of mental illness by openly discussing her bouts of depression and bipolar disorder.
That would be a significant contribution, if true. But is there any hard evidence that mental illness was widely stigmatized before she went public, destigmatized after she went public, and destigmatized due to her going public? Or is that just something people say to make her life seem more consequential?
Finally, she predeceased her mother. That will be extremely hard on her mother.