A very engaging, comprehensive yet concise book regarding the interpretation of Bach's keyboard music, in particular WTC, is Kirkpatrick's "Interpreting Bach's WTC". (a must read for Bach keyboard players. Although there are many books on this subject, this one stands out ) Also, Andras Schiff has given some interesting talks regarding phasing/articulation, as it relates to the shape (and sentiment) of those phrases mirrored in his vocal works. Also, "The true life of J S Bach" by Klaus Eidam really breathes life into the character of Bach, (and surpassing other bios in this respect, imo ).
Although Gould certainly brings something quite spectacular, and unique to Bach, (with great ability to bring out it's polyphony), one might also sample various other 'takes' on approaching his music… (sometimes i think that Gould plays all composers like he plays Bach:) Again, Andras Schiff (for sure), Hewitt, (though similar in her approach to Schiff, with a little less edge), E. Fischer version of WTC is quite beautiful, and gives a window to it's interpretive past), Lipatti, …and of course the list could go on….
Cheers