writing for specific instruments

Of course, this is a very subjective topic, and I'm not sure if
there's a right or wrong. I do know that Papa Bach was fond of arranging
his pieces for more than one instrument, and he also liked to arrange
other composer's works for instruments other than what the original was
written for. I have also read that Bach did not specify any particular
instrument when he wrote Art of Fugue. Personally, I've always enjoyed
hearing more than one take on a piece of music...the music, I feel, is
more important than the instrument. It's all in the service of the art.
As far as Debussy and guitar, I hate to be vague, but it seems I read
once where Debussy was supposed to meet with a certain classical
guitarist to get some insights into writing for the instrument....the
guitarist, unfortunately, never showed up, and Debussy died shortly
thereafter...maybe someone knows the details of this story....I love
Girl w/Flaxen Hair on guitar, and play in in the key of G...Hstick