I've had my Streamline 5 for years now and I love it to bits. In truth, until I read your post I'd actually forgotten that it has a trussrod. I've just checked and yup, it surely does. I've never yet needed to use it, but it's good to know it's there.
Regardless of what it's made of, a Streamline can sound every bit as woody and organic as my 1965 Precision or my 1964 Hofner Violin. It may or may not be a 'slap monster' but I've never played a single note of slap in my life and I have no intention of starting now.
@fretmeister is quite correct about the rather squared off neck profile, and I can see how that would put some people off. I'm a right gear tart and I jump around from bass to bass in various different bands and musical side projects, so changes in number of strings or scale length barely bother me. Neck profile is way down the list of things that I'm concerned about.