Now, of course, they will extrapolate the finding of water to the almost certainty of finding life. The NASA people are fond of doing this -- no doubt to create chatter and incease funding. Those who believe in the chance formation of life will grasp at any finding, no matter how small, to trumpet their pet theory. Life is far, far to complicated and information-laden to be an accident. Ask Anthony Flew. He was converted to theism by DNA -- information on a ribbon. He finally came to the realization that information ALWAYS originates in a mind.
Your post was good up until this assertion. Why should complexity not be a natural state of nature? Wolfram showed that huge complexity can result from very simple rules. Plato said that harmonies, or resonances would occur in natural process at selected points and not inbetween, and evolution of species wasn't even thought of then. Whitehead said that you can have complexity without diversity, which amounts to the same statement.
That being said, NASA's emphasis on their Search for Life is totally bogus. They need to hire a philosopher.