Of course the most difficult thing on the violin is always intonation. The second one is rhythm. If you play in tune, in time with a good sound that's already high level. Those three are the main things.
Ruggiero RicciColour does not make so much difference. Look at the Bach Chaconne: There is not one dynamic mark in the whole Bach Chaconne. Colours do not make so much difference.
Ruggiero RicciA good interpreter can take a piece of bad music and make it sound pretty decent, while a bad interpreter can take good music and make it sound cheap. I can tell that some people have a bad taste, and unlike on the piano, they smear around a lot, that is bad taste.
Ruggiero Ricci