Terrific post. I especially liked your delineation of the learning process the student goes through. I would tend to agree that the instructor is a key part of the equation, but I have to disagree that the style is not very important.
While shortcomings in most styles can be lessened through arduous practice, some styles (I feel) lend themselves to natural integration- "muscle memory"- better. I would encourage the novice to examine the history of any art before participating. Sport arts may help coordination and strength, but our time is better used elsewhere.
I personally practice Bujinkan budo. This is one of the few remaining Koryu schools, ancient warrior traditions. The Bujinkan is actually composed of knowledge from nine seperate Japanese warrior traditions, all hailing from Iga Province in Japan. Everything is covered. Grappling, weapons, strikes, pain grabs, kicks...the ancient traditions even included firearms and explosives work (hojutsu), though that does not tend to be taught much in the West!
In summation, although I believe some styles are inherently better than others, both diligent practice of realistic techniques, and finding a quality instructor will help you find the skills you need to protect life.