Reviews decrying the ending of Final Crisis are missing the point. Yes, Superman "wishing" the world better is contrived--intentionally so. Final Crisis is about, among other things, the nature of stories and the effect that fiction can have on the real world. By having the end of the story rest on a wish, Morrison & Co. illustrate the essence of who Superman is and affirm that the character, arguably one of the most powerful and influential creations of the last century, is capable of saving us, of inspiring us--essentially, he's capable of a lot more than punching out giant robots and lifting trains. He's all of our best qualities in one man, as recognizable as any real world figure, and more powerful than the destructive forces that pervade any decent piece of superhero fiction's dark corners. In showing us the power of this one creation, Final Crisis suggests that all stories have the ability to change and influence the real world. The Monitors, portrayed in the series as mighty gods who view the beings of the Multiverse as "germs," are oblivious to this truth and, I believe, are meant to represent us, the reader, who often overlook the power of fiction in our day to day lives.
Final Crisis also touches on the perpetual battle in superhero comics between good and evil. By showing evil winning for the bulk of the series, Morrison imagines a world--much like the homeworld of the CSA in the Morrison/Quitely graphic novel JLA: Earth 2--where evil prevails. And what do we get? Death, destruction, the loss of freedom and individuality... pretty much what you would expect. And yet, in the end, good wins. Because good creates and innovates and brings ideas to the table, rather than tearing such things down. In the very first scene of the series, humanity is blessed with knowledge and imagination and it is these attributes that save the world in the end.
Now, Final Crisis has its flaws. Much of the art towards the end of the volume appears rushed (understandably so) and Morrison fumbles some of the final moments of the series, particularly the final confrontation with Mandrakk the Dark Monitor, but none of this takes away from the scope and strength of Morrison's ideas.
With Superman Beyond and Submit included (in order, no less!), this collection is the way that the series should be read and will hopefully preserve Morrison's intent for future readers.