UPDATE (potentially very boring to all except die-hards):
Had the bass gone over by my tech, and also talked at length with Brendan who takes care of customer service at Ric - super cool guy and a real head. Here's the findings:
- The truss rod and neck are fine. It's the frets/fingerboard. Some of the crowning (or lack thereof) is inconsistent and it needs a heavy dress or potentially a re-planing and re-fret. More specifically, some of the frets have a square-ish profile like Ric's often have, and others are rounded like a traditional fret dressing would do. So it needs a big overhaul and a finer touch. This is Brendan's take as well as my tech's.
- Saddles possibly need to be swapped out so the A & D have a more radius-conforming profile. Those are the buzzy-est strings by far.
- The base of the nut doesn't actually conform to the angle of the headstock, and therefore doesn't properly support the strings over the slots or make full contact with the surface of the headstock...this is probably why what glue was previously there just snapped off. Only the front edge of the nut nearest the end of the fingerboard is really touching. Both these guys say a new nut is in order, obviously.
- Because my experience with other modern Ric's has revealed that things can be inconsistent, I'd rather have this one dialed than go on an interminable search for another one with "less issues".
So all this leads me to opt for Ric warranty repairs rather than a return/hunt for another one scenario. I sure hope that I'm not being crazy. Anyway, just thought I'd share all this minutia for the purposes of science and nerdy-ness.