Well, I find it hard to say that Bach was just refining what he had
produced in his earlier years.  I much rather believe that Bach had a style
that he liked.  What I mean is.......Bach Wrote in a style(counterpoint)
that he liked..not in a style that was all he knew.  In fact, to say that
he should have been more adventuresome is a little harsh and, I would say,
a little short of factual background.  With Bach churning out such heavily
contrapuntal masterpieces late in his life such as the B minor mass or the
Art of Fugue or even the variations on Vom Himmel Hoch, he was definitely
going against the grain.  He could have started to write in the more
"modern" style rather like Handel or Telemann(both of whom I love) but
instead he "CHOSE" to write in a style that was far out of fashion.

Wes