I haven't watched Childhood's End, forgot about that one while I was out on vacations. As for the Expanse, I don't have a problem with characters, as I never care about characters (in fact, I prefer shows where characters don't have 'script armor' so anybody could die any moment).
I haven't checked the Magicians either, didn't know it's based on some books. I don't care if they are anyway, I always judge a series on its own. If the series is good (like Game of Thrones) then it's good, regardless if they follow the books religiously or not.
Word soup, my man word soup.
I can tell by the shows you like you care about characters (Game of Thrones, STNG, Deep Space 9). All those shows are character driven. And the only way effective story telling works is when you do care that the character dies so help me Ned Stark and all those dead characters in Downton Abbey.
But I do like the term script armor, and the best stories are when anybody can die. But in order for that to be effective you have to care about the character.
BTW, just finished completely catching up with The Expanse, and I finally found a character that is compelling to me. Amos Burton, the ship mechanic and knuckle dragger. They opened up his back story and he seem to me the most iron willed in the group. He should be the captain.