What it needs, fundamentally, is the Blade Runner treatment: Kill the expository voiceover, tighten up the edit, make the ending less sentimental and more mysterious.
But yeah, they're awful. I read them when I was 12-13 and it was one of my first introductions to the idea that sequels to great books could be so bad (and then for some reason I went on to read the Brian Herbert Dune prequels, which are even worse). Read the first one, and pretend it stopped there.
Clarke was so much of a better writer than the [2010|Rama] sequels indicate. He would not be able to screw it up so thoroughly without extensive "help".
Clarke also made some good partnerships - Richter 10 is a very good book. Sadly, the partner died and never worked with Clarke again. Gentry Lee would be my main suspect.
Although it seemed implausible in the setting that humanity wasn't immortal given some of the technology.
2010 is a good follow on to the 2001 book, and answers some of the questions the first book left while expanding the mysteries and the sense of wonder.
My wife and I still quote it when answering questions such as what's for dinner.
"Something wonderful".
8<-------------------
"You said that all the old religions have been discredited. So what do people believe nowadays?"
"As little as possible. We’re all either Deists or Theists."
"You’ve lost me. Definitions, please."
"They were slightly different in your time, but here are the latest versions. Theists believe there’s not more than one God; Deists that there is not less than one God."
"I’m afraid the distinction’s too subtle for me."
"Not for everyone; you’d be amazed at the bitter controversies it’s aroused. Five centuries ago, someone used what’s known as surreal mathematics to prove there’s an infinite number of grades between Theists and Deists. Of course, like most dabblers with infinity, he went insane."