The quality of a book is generally judged by the words in it, in addition to the story. It's not just what you say, how you say it also matters.
If not a complete counter example, Legend is a book where the rule loses its effect. Legend is certainly not the best written book ever, but it is most definitely one of the best books ever written.
David Gemmell never finished school, since he was expelled at the age of sixteen, and the unrefined writing is apparent throughout the book. He struggled to tell his story, but he had a hell of a story to tell. What the book lacks in sophistication of wordsmithing, it more than makes up for with the raw power of the story.
Allow a thought experiment for the moment: Strip away all the decoration in a typical book, all the character action/interaction that exists for flavor, all the worldbuilding, all the prose, exposition, and clever tropes. What are we left with? Usually very little. Usually a basic plot, that we're lucky to even partially connect with. It might even be an intelligent story, or an imaginative one. But it's ultimately weak, skeletal, and insignificant in almost every way. It might even be non-existent.
Luckily, our world has been gifted with a book like Legend where we can prove such a thought experiment wrong. Strip away the decoration and frosting from Legend; cut it down to its most basic elements, and we are still left with a book worthy of the test of time.
In the Iliad, Achilles was given a choice by the gods: To live a short, glorious, heroic life that will end violently but be remembered, or to live a long, healthy life and eventually suffer the fading effect of time upon his name. We all know what choice Achilles made, and Achilles is remembered as one of the greatest heroes ever to come from the ranks of humanity.
In his own way Druss, the main character in Legend, faced the same choice. Fade into old age and senility, or face down your death with defiance at the cost of a shorter lifespan.
Yet Achilles is not the only hero who is remembered through the ages. In fact, the greatest hero of the Iliad is Hector. Where Achilles is remembered for the glory of his life, Hector is heroic for the manner of his death. Knowing with absolute certainty that to face Achilles in a duel means death, he accepts the challenge anyway. Not to be suicidal, but to die in the manner he tried to live. What makes a man (or woman) great, or heroic? What does it mean to die a "good death?" For that matter, what does it mean to even live a life worth living?
Overcoming great obstacles and succeeding is not compelling enough. Fighting, failing, and dying knowing that your name will be remembered isn't even heroic enough. The true hero, is the one who fights against that which he knows he cannot possibly defeat. Not for the remembrance of his name, or the glory of his cause, but for himself. Humans often die for one another. A mother takes a gang member's bullet to save her child, a man on life-support wants the plug pulled so his heart can be transplanted to save another, or a soldier dives upon a grenade to save his squad mates. What makes one case more heroic than the next? What if nobody was around to recognize such sacrifice?
If the mother knows with certainty that jumping to take the bullet will still not save the child from death, yet does it anyway, is it still heroic, or foolish? If nobody is to witness that mother's sacrifice, should it affect her decision to commit it? If nobody pulls the man's life-support plug for him, but in a rare act of clarity he manages to pull it himself while he is alone in his hospital room, does it detract from the glory or worthiness of his death? If the foxhole of soldiers becomes surrounded by an insurmountable enemy, and if the soldier knows without a doubt that diving upon the grenade will not save his friends from the battle. Should he do it anyway? No one will know he did such a thing.
No medal will be given, nor monument raised to his name.
What makes a death a good death? And what makes a life worth living?
The characters of Legend are the characters within us all. Fear, doubt, and futility are all present, but so too are the traits which make us greater than the sum of our parts. Honor, courage, duty, and yes, even love are all necessary components for a heroic tale of such resonance.
David Gemmell wrote Legend, as he was waiting to find out whether or not he was going to die from cancer, and it is his attempt at dealing with mortality. What does it mean to die well, or live well? What does it mean to be a man? Is love even worth the effort if it is destined to last only a brief moment and end in pain?
Socrates said the unexamined life is not worth living, but perhaps the unexamined death is not worth dying either. All life leads to death, but perhaps all death should be embraced with the joys of life.
Very few books have had an impact comparable to Legend, and as I said, for all it's technical flaws it is one of the finest novels ever written. Gemmell's fears are my fears. His hopes, my hopes. Legend was his first and greatest book, and its very existence makes the world a fuller place, and humanity wealthier.
R.I.P, Mr. Gemmell, you've earned it.