I'm not a fan of Moore; kind of find most of his stuff boring (from Watchmen to Tom Strong). However, i see why people like his stuff and honestly, no Marvel writer is like him.
People say Hickman is close, but he lacks the range and personality in his stories. They all read and feel the same, plus most of his characters are rather hollow. Moore knows how to write a little of everything, while Hickman is more about grand, "epic" scale tales and less focused on the human element.
If you're looking for someone similar in skill, you'll probably find someone better in the Japanese writing scene, like Naoki Urasawa, Satoshi Kon, or Daisuke Igarashi.