I would tend to agree in general (ala Ric's being maple body/neck) that this is true (combined with what I mentioned) to lead to an ultimately bright bass. However, where the real animal lives with any instrument is how each part combined results in a holistically awesome sounding instrument. Think of it like a high-end (Trek) carbon road bicycle; it's how the carbon is woven, how it is shaped and where it allows flex or promotes stiffness that will result in an amazing response when riding it. Similarly, a bass can be 'tuned' by all of the parts including wood choices. Staying with the Trek analogy - I toured their factory in Wisconsin and they related a story where they set out to build the stiffest carbon bike possible. (one element in it's performance character) It conformed in appearance to their current production bike but all internals (how and where the carbon was woven) was geared to ultimate stiffness. Looked exactly like their production bike which performed amazingly, weighed the same but was unridable/dangerous. (too stiff) Skepticism over wood as being important aside - I could build 5 P-basses, each with different woods, bridges, pu's, electronics, strings and nuts - and each one would have it's own character different from the others. Point being, an all maple bass may be bright, but may not sound great. Even nuts can be made of hybrid materials (brass/bone) to promote tonal nuances.
As far as order of why a bass sounds like it does, it's pu's/electronics, neck, strings, body, everything else.