AVA219: Would a given piece of music have the same "feel" if transposed to a different key?

This question was sent in by Russell, and he writes: Greetings, Vidas. I found your course while searching for guidance as how to educate myself in music theory. I have a piano and an old Hammond organ, but I am not a musician. I read music, but only with difficulty. I desire to learn music theory because I do not understand many things about music. Most importantly, would a given piece of music have the same "feel" if transposed to a different key? For example, why did Bach choose D-minor for the Toccata & Fugue, BWV 565, and C-minor for the Passacaglia & Fugue, BWV 582? Would music written all in the same key be boring or tiresome? Or does the key (other than major or minor) enhance the effect of a particular piece of music? It seems to me that, for me, a good starting point would be to practice and memorize scales and chords. I love classical organ, but I wonder how an organist manages to keep track of multiple voices, such as in a fugue. I wonder whether some brains are "wired" with this capability and others are incapable of playing polyphonic music. By the way, are organists typically ambidextrous? At age seventy, I do not expect ever to become proficient on the organ, but I do find your instruction enlightening and welcome. Russell