I stand with Bertram Turetzky in that a "First class instrument shouldn't play transcriptions in public".
That of course is not always true. Some transcriptions are really great. Some are even better then the original piece. I prefer the guitar version of Albeniz' Asturias to the piano version for example.
You are right that each instrument should find his own 'voice' and repertoire. I have to admit that I prefer listening to cello pieces much more than double bass solo pieces. So I can also imagine why classical composers preferred composing cello solo pieces.
