Some of us never watched the original and 4400 almost made me want to watch The 4400 but I haven't (so keep that in mind as you read this review).
I would have liked to see more character development at the very start but I guess this is the element of surprise they might be creating.
As for the colour of the characters, I'd like to make a few observations. Most shows post-2020 are focusing on the real life issues in society (FBI and its spin offs, NCIS and its spin offs, Bull, Seal team, Law and Order spin offs etc). It makes the shows relatable and appeal to the masses who are not just into soap opera or fiction material. I'd say that is what 4400 is doing (it's a reboot and so they get to change what works for this generation). Maybe we will see a representation of more backgrounds or ethnicities as the story unfolds but we have to watch it to see it, right?
Enjoy it as I'm doing.