Well worth it IME.
It may well be well worth it (and I'm pretty sure that I would do the same mod if I bought a 4004), my point is WHY you have to do the modification to an already high value instrument.
Doing the mod on a brand new instrument would surely invalidate the Manufacturers Warranty, so not only do you have to pay an additional amount on top of purchasing an already high value instrument, you are also invalidating any potential comeback you may have against the manufacturer should anything go wrong.
On a second hand instrument, the Manufacturers Warranty is already invalid, so no issue there, you're just having to spend out on an instrument you've just spent a fair amount on anyway.
Surely a twin pickup instrument, especially a bass, needs either a volume control for each pickup, or alternatively a "blend" pot (or even twin stacked pots, you could keep the selector switch as well).
I am, of course, simply playing Devil's Advocate here, as I don't expect anyone at Rickenbacker to take any heed of this, and I don't expect them tom implement any control layout changes on either the 4003/4003s or the 4004. I'd love to have a 4004 (in either L or Cii variety), and if I ever did, the control layout would be modified.

After noodling with it for a while with no amplification 