Hence, IMHO, a tremendous weakness in libertarian thought.>>
That is really it's strength. The only thing libertarians need agree on is a noncoercive society. While I'm aware that people can argue about exactly what this means, it really isn't ambiguous most of the time, especially compared to other ideals such as a "just" or "moral" society.
<< Now, again, just what is libertarianism?...How do you sell a point which can be defined in so many different ways? The non-initiation of force and laissez-faire economic stance of libertarianism is highly attractive. But is that all there is to it? >>
Well, every political philosophy from socialism to conservatism is defined differently by different thinkers. But, yes, non-initiation of force IS basically "all there is to it." The disagreements are ironing out what this means, which is obvious on many issues and less obvious in others (e.g. abortion). What makes libertarianism fundamentally different is that all other political philosophies are based on a model like Plato's Republic --they have a very specific vision of an ideal society. Libertarianism, on the other hand, allows for many different "utopias," the only condition being that they don't infringe on one another. This is probably an ideal that will never be fully realized (like any ideal), but it's the one that allows for the most freedom. So when people complain that it's too "vague" or encompasses too many possibilities, they are missing that this is the very point of libertarianism.
You say that this is a strength of libertarianism, right? But let me ask you this question. Does the concept of "over-diversification" mean anything to you, as in the business model?