It was also wonderful to hear the fully scored version of the sixth, complete with two viola da gambas! Though kind of sad, as those lovely instruments were on the wane.

I totally agree with your point about the variety. Bach seems to be pushing the possibilities of key treble register and obvious solo instruments, for example, violin, recorder, trumpet, oboe. Featuring the viola is a bit unusual and creative, as in general the instrument floats between playing backup to the seconds or adding flavor to the basso continuo squad (notable exception is opening for the forth concerto.)

I find it interesting that the only member of the continuo group to get true star treatment in the Brandenburgs is the harpsichord and recall reading (in extensive liner notes ages ago) that this was an innovation of the fifth concerto. During the concert, I found myself wondering, what about the cello? The part in the sixth concerto is pretty important with many vital phrases played by the cello, but that instrument never really gets the center stage in any of the concertos. If course, Bach more than makes up for this slight with the cello suites.

What a shame, Mr. Schiffer. To hear the complete cello suites in one or two sittings would be amazing. Something I have hoped for each season. A compromise: six concerts, each featuring a cello suite with complementary pieces, drawn even from outside of Bach or the baroque era.