1. The Viol Da Gamba fell out of favour later on, however the double bass still keeps some of its characteristics like its tuning
2. I would have to guess ornamentation (don't quote me on this though)
If the musicians are highly skilled then it allows the stranger to come up with a more complex piece, but if they aren’t, then the arranger has to come up with something more simple. the talent directly correlates with the difficulty of the piece :)
