I read this book a long time ago, it's your classic "peaceful alien invasion" story from what I remember, right? And the aliens look like {censored/no spoilers from me}?
I dunno, I didn't think that story was a particularly good one to transition to the big screen. I mean, it's interesting and all, but it seems it's all been done before with V and all. Aliens come, seem peaceful, humans realize what aliens reallllly look like a bit later, etc. Not much new here.. or is there? Clarke wrote so many more books that seemed a lot more ideal for the big screen, but tbh I can't even remember the names of many. Guy has just written so many books, and I read through many of them when I was younger and a lot of them seemed like TV/movie candidates. The only reason I would make Childhood's End a movie or TV show would be for that dramatic "here's what the aliens look like" reveal. But that's just one moment and has been done before with V, sort of. Maybe I don't remember why else they might have picked this story though..
I guess if they change things around a bunch they can adapt this story for the modern day and make it a bit more unique, but.. then is it really going to be still Childhood's End? I hope they don't change the main part of the story, the physique of the aliens.