I actually had an exchange of views with Christie Golden via e-mails for a while around the time the "Dark Matters" trilogy was publiced and she did share my opinion that Kes had been mistreated by those in charge. She also mentioned that she had to re-write parts of the "Dark Matters" books, at least the last one due to the s**t episode in season 6 which destroyed Kes and messed up the story Golden had written so far. She didn't like the s**t episde and couldn't understand why the brought Kes back only to destroy her.
Personally I found Golden a very sympathetic person and I also enjoyed her previous books "The Murdered Sun" and "Marooned".
I can understand that Golden couldn't contradict "canon" then by simply returning her to Voyager but I do think it would be possible to restore kes back to normal and re-introduce her to Voyager in upcoming books.
Without being big-headed and without putting down other more skilled writers, that's exactly what I did in my Kes come-back story "Coming Home" where Kes is restored back to normal and at least temporarily re-instated as a member of the Voyager crew (you see, I wouldn't contradict "canon" either by bringing her back permanently in season 7 when she wasn't in season 7 in the TV series.
But I had no qualms about wiping out other things I didn't like. It took me five minutes to get rid of that nine-year lifespan stupidity and energy-being mumbo-jumbo and one minute to erase the damage made to the character in the s**t episode in season 6.
All that was necessary was a bit of will and imagination. Maybe some writing skills too!