It's been said and I agree with: "It's not the musical instrument, it's the musicianship". Some instruments are louder such as bluegrass banjo or uillean pipes but they can be monitored by the player by muting or playing without regulators....all kinds of solutions can be found to keep the dynamic range from intruding excessively. I have heard tasteful electric guitar and keyboard played with accoustic instruments by excellent players who have added to the music. True with electric bass players too. Any instrument in the hands of a musical person can be made to contribute. Accordians can be modulated dynamically.
Musical expression is largely a matter of "attitude" IMHO.

Frank Hamilton