Heinlein’s work did drastically alter from when he was writing YA novels to the later novels. The earlier works, which I regard as being more truly what Heinlein was about, were very hard science oriented. I’ll agree that the later works are more social science oriented.
I prefer my SF to have both hard science AND social factors in it, though I’m willing to give up the social bits in favor of a hard SF story. I loved Robert Forward’s works, for instance, despite the fact that he couldn’t really write believable entities. His worlds and situations were fascinating enough to make up for it.
I separate fantasy and SF in my own library. My current outrage is for the combination of paranormal romances with SF/fantasy, and for the combination of horror/SF/fantasy. Paranormal romances are primarily romances, IMO, and I am sick to death of reading about yet another Extremely Alpha Male who can’t resist Our Heroine. There are a few good paranormal romance writers out there, but damned few.
Bingo! I haven’t re-read his fiction in decades, but I always liked his non-fiction better. And I liked his chatty intros, both to short stories and to his collected essays. I always assumed he was being self-mocking when he preened. And I kind of liked being called Gentle Reader. I was much older when I discovered that this wasn’t his own invention.
Piers Anthony - I changed. Just as a datum - when I was reading and enjoying him, a librarian mentioned that he was the most frequently stolen author in the library.
I think my attitude is similar to yours. I love Heinlein, but did not really enjoy those later works. They were so self-indulgent it was almost like watching the author masturbate. I loved his characters, but he loved them a bit too much — I think he was the only one who enjoyed watching Mama Maureen Sail Beyond the Sunset. The rest of us were happy with the visit we’d had with her in Time Enough for Love.
I have one positive thing about Number of the Beast, though — it inspired me to read Edgar Rice Burroughs. Up until then, I’d always seen it on the science fiction shelves in the bookstores, but automatically assumed it would be dreck due to the illustration of the 4-armed green man and the semi-naked woman on the cover. The love for those books in his own made me take a look at them, and I really loved them.
I’m also on the “OMG, Did I really like Piers Anthony” bandwagon. I started off with the Adept series, which I enjoyed, and moved on the the Incarnations of Immortality, which I also enjoyed. I read the Mode ones, but found the teenage girl abuse themes pretty disturbing. Then I read the first couple of Xanth books, but then when I started to see that the sexualization of young girls was pretty much a constant theme, it made me positively sick. I felt like I needed a bath, so I dropped him.
Along the way, though, at some point I picked up his “Bio of an Ogre.” It was positively hilarious, though that was unintentional. He’s such an egomaniac — this was just his whining about how he was misunderstood, not recognized for his genius, harassed, etc. I guess it makes me a bad person to be laughing at someone who’s just a bit touched in the head, though.