I just read Mr. Callahan's review of Final Crisis, and how the concept seeds started way back in Morrison's career. Very cool. Particularly how the Mr. Miracle Seven Soldiers mini ties in.
It misses a big problem (and I'm not talking about the marketing snafu around Batman's death). Final Crisis has no emotional centre. It has no main character. All the potential main characters are off doing stuff in their own books, like Superman Beyond. Mr. Terrific or Shiloh Norman would have been great central characters to focus on, allowing the spinoffs to focus on the other characters.
The second problem is that Morrison throws too many ideas at the wall. They are all really fascinating ideas. Wonder Woman alone is crazy cool. But it feels like the writer's equivalent of feeding paint through a barn fan, then calling the splattered canvas art. Of course, he would have been able to get away with this if it was filtered through a central character's reactions.
But as it stands, it's quite fascinating how Morrison weaves thematics and ideas into Final Crisis, but if you don't care about the characters in the story, then there isn't any reason to care at all.