I guess I just don't see what a theory of personality ADDS to behaviorism.
I would argue, depth. And so, more intriguing avenues to approach a solution.
Taking this a bit further because it's an interesting side-discussion, it strikes me that what we're really differing on here are different philosophical approaches to the mind, and the question of free will.
I would suggest that Behaviourism is essentially hard deterministic is its nature; it presupposes that everything can be understood through a causal chain. That will naturally appeal to scientists, and psychology these days has a lot of people entering it with that perspective, and a lot of courses are heavily structured around that scientific approach.
By contrast, Psychodynamic and cognitive approaches (and personality theories can be classified as broadly psychodynamic) are essentially either compatabilist/soft deterministic (eg Freud) or outright libertarian (eg Jung): they either temporarily put to one side whether there is a causal chain that might theoretically some day be understood or outright disregard that possibility to the point of effectively denying it.
Instead they focus on the internal state of the mind. I suggest that this introspective element paradoxically allows psychoanalytic approaches to be a powerful short-cut to understanding behaviour; one no longer needs to decipher the contingency chain, one simply needs to see the overall emergent pattern. It is not scientific - an introspective approach can never be - because it is unique to the individual/relationship. Its power is that it is heuristic rather than algorithmic.
One final thought: you clearly lean heavily towards a behaviourist model, whereas I have a lot of sympathy towards a psychodynamic model. How did we end up with those different philosophical leanings?
To answer that, a behaviourist (as I understand it) would have to decipher the detailed chain of events responsible for structuring a mindset that favours that worldview. Unless one believes in the transcendental, I agree that it's theoretically possible to do that, but it would take a
lot of time and effort and at some point, the haziness of human memory would make it impossible on a practical level.
But if you take a personality based approach, I suspect we'd get to a working explanatory hypothesis much faster. That's what I mean by it being a short-cut to finding avenues to approach a solution. The avenues may end up being blind alleys sometimes, of course, but that's the price you pay for this technique.
Cognition is so complex an emergent phenomenon that it strikes me as, well,
tiresome to go through the nuts and bolts of explanining its emergence through behaviourism, when there's a potential short-cut there for the taking.
This is an interesting discussion by the way, thank you. I might write a bit more about it on my blog at some point.