Even if Bob hadn't sweet-talked me, I would vote both for having this
ongoing discussion and for keeping it on *one* primary list. The
latter is important to insure that *all* participants are in on *all*
of the discussion and, perhaps even more importantly, to preserve the
integrity of the archive.
In my opinion, this kind of discussion is exactly what Phys-L is for
(and I am posting my response only to this list.) I'm a little less
confident of saying that about PhysLrnr notwithstanding the fact that
Bob is a long time central participant in the PER community and
intends to produce a "research-based" text. It seems to me that Bob
is perfectly capable of bringing the appropriate PER sensibilities to
his efforts. Furthermore, it seems to me that what he would really
like--and what I and I think others would also like--is a more
freewheeling and regular discussion about very specific, novel, and
effective pedagogical approaches.