Warwicks are very well made basses, and due to the wenge necks, very unique sounding.
The Thumb is the most 'Warwicky' of them all, mostly due to the combination of thick/wenge/ovangkol neck and bridge-pickup placement... especially the 5 stringers.
Ridiculous amounts of growl and punch (which is why I own one).
Very dry sounding, and low-mid rangey.
Excellent for rock/metal/tap and yeah, thumbing.
Traditional, Thumbs are not; modern, they most certainly are.
A Streamer Stage II will get you the most versatility combined with that modern Warwick growl you can get, and you pay for it. A Streamer Stage I will be more traditional sounding, but still have that signature growl due to the neck.
By the way, Thumbs (at least the 5 string bolt on I have) don't neck dive, they sit horizontal, or just above, like has been mentioned already. Don't let others convince you of something so subjective as neck dive. Where you want the headstock to be as you play is relative to your taste. Of course, I had a Gibson that wouldn't even sit horizontal, and always wanted to head dive to the floor. Now that is neck dive!
You want the headstock out and just above your waistline, get a Thumb or Corvette.
You want the headstock up by your ear, get a Fortress or Streamer.
It's all relative to your needs, playing style, etc.
I say, get a used Streamer stage I or II and enjoy.
If you don't like it after a month or so of getting used to it, it will sell pretty quickly.
I'd advise against buying a new Warwick, because they are imported from Germany, and you'll pay a ton of money for one, with no hope of recouping (low resale-from-new value). Think Audi, Porsche, Mercedes...
Might as well order a custom shop one at that point and get exactly what you want for high dollar.
Which I totally wish I could.
With a used Wick, you get what you pay for, and often more.
Because again, they are very well made instruments.
Heavy? Um, it's a bass, not a ukelele.
I've tried balsa wood weighted basses, and they all seem to suck tonally. Flat and lifeless, bleh.
Unless you have serious back/neck/shoulder problems, weight shouldn't be an issue with a well made strap and regular exercise. IDK, maybe I work out more than other bass players, but weight is a none issue for me, and I'm no large mammal type human, pretty average really. Or maybe I just need to tour more. (well, I certainly need to tour more!)