Random comments from one who has not followed this thread:
The biggest problems I have with picturing flux as lines is that there
are never enough of them drawn to give a good idea of how smooth the
field is, and they are seldom drawn in three dimensions ("The Mechanical
Universe" does this well).
Neither electric nor magnetic fields are real. This is most readily seen
by observing their nature from different frames of reference. For example,
electric fields seen in one frame of reference may vanish entirely in
another. They are merely mathematical forms which are useful in describing
interactions. The question then arises: "Is the electromagnetic field real?"
I am of the opinion that the electromagnetic field possesses an essence of
reality because it can persist as electromagnetic waves in the complete
absence of sources.
Description of Nature is the central objective of science. Explanation
of Nature is beyond human competence. Do not confuse good, logically
consistent description with explanation.