It is a sad fact (IMO) that the science fiction genre seems to contain some real tripe. I think part of the trouble is that it has infinite possibilities that can easily exceed a limited imagination.
The thing I like about Heinlein is that he uses SciFi as a vehicle for provoking philosophical thought by presenting challenging ideas. His most famous is Stranger In A Strange Land, his most controversial by a mile is Farnhams's Freehold. His one failing is that his Bible Belt background interferes with his attitudes towards sex. Somehow he just can't write it. Fortunately, he doesn't try too often although there is a creditable attempt in one small part of Time Enough For Love. He would be thought a little too right wing for the delicate sensibilities of most of the members of this forum although 'Jerry Was A Man', the tale of a legal battle to give a genetically modified chimpanzee human rights might appeal. At least he does give background and supporting argument to his thoughts.
"I do not agree with what you say, but I'll defend to the death my right to be offended by it."