While Kes was certainly not the best Trek character EVAAR and I overall prefer Seven, I don't think Kes was a genuinely damaging character and Jennifer Lien was a competent, wonderfully quirky (I'm a fan of the MIB cartoon and she gave a better account of herself than Avery Brooks in American History X).
I disagree about the Avery Brooks part and only that part.
Avery was outstanding in American History X. He even has the most important line in the film. "What has all this done to make you life better?" is single question that makes Ed Norton's character rethink & change his life for the better. His bond with Brooks is pivotal to that film. The film would have fallen apart without Brooks character and what he represented. He was the only Black man during the entire films run that he trusted and thought differently of.