I don't blame you at all for wanting something besides brushing--a lot of folks sort of like having their fingers attached to their hand in the same order God put them there!
In my experience, dental disease has a huge genetic component that we can't do anything about. Your cat probably also had inadequate nutrition as a kitten before you rescued her; not to mention her mom.
Since she's already on raw, perhaps she would be willing to try something a little odd. Try leaving the raw meal partially frozen, so she really has to grind on it with her back teeth to eat it. I have a buddy who makes a commercial raw diet, and she's had great success with this.
I've heard good things about Wysong DentaTreat. Iit smells very cheesy, pretty good actually! It took a little getting used to on the part of the cats but now they eat it without hesitation. I mix it into my cats' homemade food; they still have a little "red line" gingivitis but no periodontal disease. I still do dentals on them every year (3 of them need shaving so I'm sedating them anyway). There's a similar product that I can't remember right now but I'll ask the store who carries it (remind me tomorrow, okay?).
Purists will sniff, but I have had great luck with CET Chews and, of all things, kitty Greenies. Both of them will actually pull tartar off the teeth, provided the cat actually chews them. I know a few cats that swallow Greenies whole. Geez.
Recently I attended a lecture by our local (very rich) vet dentist, and he said that of all the supposedly tartar-control Pounce-type treats, Greenies is the only one he recommends for cats. Not for dogs, mind you--and the ingredients in dog Greenies are nasty, but the kitty ones are okay. Cats love them; I have yet to meet the cat who won't (eventually) eat them. He also likes the CET Chews.
Here's my experience, and honestly, it surprised the heck out of me. My short-haired cat (who hadn't been shaved, of course, so hadn't gotten as much dental care) ultimately developed quite a bit of tartar, and from the look of things he was going to need some extractions. It was going to be a bit before I could bring him in. Meantime I had just discovered Greenies and was using them as bait--cats climb all over the computer, I throw a handful of Greenies across the room, cats leave!
And wouldn't you know, when I did the dental 2 weeks later, most of the tartar was gone and he didn't need any extractions at all!
BTW, don't be too worried about the anesthesia. I'm told (by the anesthesiologists of course) that there's no cumulative effect from "serial" anesthesias; once the animal recovers it's as if it never happened. Well, I probably wouldn't go quite that far, but done correctly anesthesia is very safe. Just make sure your vet is using isoflurane or sevoflurane gas, and has adequate monitoring (the main thing you want is a real live tech or assistant standing there watching to make sure the cat is breathing, little details like that.) In my book, untreated dental disease is a whole lot worse--it's painful, and way more dangerous than even frequent teeth cleanings (say, every 6 months). As long as your pocketbook can stand it, that is!