I have not read the books, but I can still say that the movie was not very good. I am aware of the changes from the books, however. There's a YouTuber named Dominic Noble who has a series called Lost in Adaptation where he compares movies to the books they were based on to describe what they changed, what they kept, and his thoughts on the adaptation as a whole. He covered both Interview and Queen of the Damned.
As for why Anne Rice is an asshole for that, I didn't post her full quote, but I did forget to say that this was a couple years before the film actually entered production, so it wasn't that she was upset about them trying to use her name without using her writing (and for the record, she went all over the place when it came to whether she liked the film or was disgusted by it. In 2001, she was OK with it at least enough to let her name be used in marketing, then in 2003 when she saw the film she dismissed it, despite having said in 2001 that she was pleased with the final film when OKing the use of her name in marketing). This was her full quote when asked about the movie in 1998, to give a bit more context on why I think she comes off less as understandably upset over the movie being made and more bitter that they didn't have her write the script.
It could just be that she's highly protective of her property, but she came off as more sour grapes with her comments, like "If you aren't going to have me do it, it's going to suck anyways, and any writer who you'll try to get will suck." That's not really me paraphrasing, either. This is the direct quote.
"Not very long ago, less than a year ago in fact, I begged the executives there to let me write a script for THE VAMPIRE LESTAT for union scale (the Writers Guild won't let you write it for free) and a deferred payment not due until release of the picture. They simply weren't interested. It was very painful for me, as I had been talking to a new director they'd hired and we were both excited about the idea.
I felt snubbed and hurt and have not bothered to approach them since. The young director is supposed to be developing THE QUEEN OF THE DAMNED which I think is a bad idea, and basically a doomed project.
In spite of their showing no interest in me as the screen writer, they have not been able to find one themselves for this bizarre idea of THE QUEEN OF THE DAMNED. I'm not too surprised. I think any respectable script writer would be crazy to tackle that novel without having fully developed the background story of Lestat. Anyway, that is where it is."
I'll admit that part of my reading of that is colored by knowing how viciously unfriendly Anne Rice is towards anyone doing anything with her work that she doesn't approve of, like fanfiction, or how she's shown an incredibly thin skin towards anyone critiquing HER work, but it still came off as more petulant to me than anything. "Fine! Your stupid project is lame, anyways! Good luck finding someone better than me!"
ETA: As for Akasha's accent, I didn't find it offensive in the same way you might be thinking. I just legitimately don't know what her accent was supposed to be. She was trying to do some sort of accent, but I couldn't tell what other than "not her normal accent".