I actually own a copy of Kingdom Come. I didn't find myself enjoying it that much when I read it years ago because, as mrsMxyzptlk suggested, it is a bit confusing when you aren't familiar with all of the characters. Back when I read it, I wasn't, but it might be worth me giving it a second read. I can't remember who all is in the story besides Superman and Wonder Woman, but I am now more familiar with the DC characters than I was back then. I might be able to put more things into the proper context now.