When you say "the pickups are notoriously weak", what are you talking about here?
Weak as in relative to the music you're playing?
Or weak as in a low impedance figure (under 7-8k ohms)?
Definitely lower impedance than the Nordstrand's?
I would say that many players have made big noises with low output pickups, and maybe you just need to EQ your non-Nordstrand loaded basses differently to the Nordstrand loaded one.