fantasy can be pretty diverse. I mean if you ignore the 99% of it tht reads like LOTR fanfiction, of course.
Not that I'm admiting to reading fiction or anything.
Man I read a lot of this shit as a teenager, and it's really not very diverse at all in practice! I'm not saying it never is or that it's impossible to be, but your post is kind of misleading, because like you said 99% of it is poorly-written D&D/Tolkien garbage that reads like fan fiction. The problem extends to sci-fi too, once you realize that they appeal to the same demographic and writers, and as a result, 99% of sci-fi by extension reads like fantasy with lasers and spaceships. It's too bad because I've read some pretty good works in both genres and not only do most authors have no clue what the fuck they're doing a large portion of the time, but it's never going to get any better because fantasy fans gobble that shit up without even acknowledging the genre is as rote and uninspired as it could conceivably be without ACTUALLY BEING the same book over and over again. For a while I thought Goodkind might be a passable writer (even good!), and what I liked about him was how he attempted to write females as if they were different from male characters, and not just men with tits/feminine battle armor (it was actually his books that made me realize how badly almost all female characters blow), but he's got his own issues too, not the least of which seems to be a pretty noticeable dose of sexism in all of his books.
Also I always thought the Shannara books were very formulaic, because I read like five in a row and they literally all followed the same basic sequence of events, but I liked the SWORD in the first one when I was sixteen or so. I was reading it, and it was a pretty long book, and I was expecting the sword to perform some kind of potent, darke majicks, and instead it just made the guy ACKNOWLEDGE THE TRUTH//FACE THE FACTS and was kind of completely anti-climactic. I was pleasantly surprised by that part of it, but yeah it's not a very good series.
Also what is Venture Bros. even influenced by? You realize it's a satire, right? Like it's obviously a parody of Johnny Quest, but I wouldn't list that as an influence, so much as the subject. I think you should differentiate between parodies that are based on certain things, and serious works that are just rehashes. Like, even of Venture Bros. was bad, it wouldn't be the same as that other stuff.