A couple points:
Castaneda appealed to some people, and may even have helped some people, in part because he ripped off other traditions besides Native ones. Most of what he passes off as NDN, Yaqui, Toltec, is actually Hindu, Taoist, Buddhist, or other eastern beliefs. The Tensegrity nonsense, for example, is Tai Chi with pseudo Indian names slapped on it. He even lost a lawsuit that came from his own Tai Chi master for ripping off his system.
Part of his appeal was also that he made racism against NDNs (the romanticized image of the Noble Savage in particular) sound appealing to the counterculture. I don't know of that's what appealed to either of you, but that's undeniable part of him. And we can easily find plenty of examples of his followers who love him to death, but explode with racism against NDNs once they hear an NDN criticize him.
As for being a good writer, I think he's one of the worst examples of overwriting I've ever seen. Bloated, incoherent, pompous, sometimes just plain gibberish. Often part of his appeal from his supporters come from those who think being dense and hard to understand equals being "profound," esp those who are easily impressed by a big vocabulary. The clearest evidence of him being a bad writer is the decline in readers in each successive book. Looking at online discussions of his books, one can see plenty members of his own cult who admit they can't even understand much of what they read, and didn't even finish the first book.
Can't say I blame them. It's like water torture for me to wade through anything of his since I teach my students to write clearly and say what they mean, straight out.
Cleargreen is mentioned in several threads in here, but we don't have a thread specific to it. Since they're an abusive cult who continue to harm many people, a thread is badly needed.