Nietzsche's philosophy is clearly an alternative to religious thinking because it combats the very foundation of religion. I, being an atheist believes that his teachings should be more widespread than religion its self because it is more practical in today's society. Is summary, religion is an outdated practice and needs to be replaced with more modern thinking, Nietzsche's philosophy.
Many people are puzzled, even shocked by Nietzsche's philosophy. However, many people don't take the time to truly understand his philosophy. For example, when he says "Gott ist tot", or "God is dead", many people think that he is just proudly (and bluntly) stating a nihilist viewpoint on metaphysics. However, it is way more complex than that - although he was an atheist, Nietzsche is referring to the decline in objective moral authority that was going on in his time. He was concerned that this would lead to a society led entirely by reason, in which emotion and initiative would not be recognized as important or valuable. Nietzsche can offer so many other insights into the world of his time, and the modern world as well. Although I believe that religion and Enlightenment thought can offer insights as well, Nietzsche's philosophy is the one that is probably the most radical and initiative, and can probably improve today's stagnant society.
Should be considered an alternative to religion by whom? Alternative to what kind of religious thinking? Faith?
The question is so vague it's almost impossible to answer. In fact, those that answered in the affirmative must not understand what they're talking about since the question isn't properly framed.
NIetzsche's work encompasses a transvaluation of values. That's about it. The rest of his work is really a deconstruction which leads him to other possible values. He doesn't come up with a morality or any definitive philosophical system. The main thing he does is question the assumptions made by religious systems and society. He does this in wonderful detail and penetrating lucidity.
He's more like a revealer not a presenter.
Anyone who believes Nietzsche's teachings are an alternative to religion doesn't fully understand Nietzsche. He was an atheist, as am I, but was deeply concerned over what the effect of vanishing of religion and the values associated with it would be on the modern word. He believed that losing faith in a belief system could lead to a lack of trust and a tendency to lose faith in belief systems in general. In short, atheism leads to nihilism.
And the full quote is "God is dead. God remains dead. And we have killed him. How shall we comfort ourselves, the murderers of all murderers? What was holiest and mightiest of all that the world has yet owned has bled to death under our knives: who will wipe this blood off us? What water is there for us to clean ourselves? What festivals of atonement, what sacred games shall we have to invent? Is not the greatness of this deed too great for us? Must we ourselves not become gods simply to appear worthy of it?"