[brudgers]

By "tuning was what it was" I did not mean that JS Bach's organs were out of tune with themselves. But rather the obvious thing that pipe organs can't be retuned to arbitrary temperaments in a practical manner.

And to be clear, Well Tempered Clavier is generally believed to have been written for harpsichord not organ. There is not more evidence that it was a plea than that it was simply JS Bach writing experimental music for the latest technology.

[bluGill]

Granted tuning an organ is an all day (or even multi-day) problem, but it is perfectly possible to change temperament. Tuning a piano to change temperament will take a skilled tuner some time as well.

harpsichord - I knew that, but couldn't think of the right instrument...