You are mistaken. I can play songs in D and in A on mine, and the use of G or G# or (C or C# on the bass string) makes many trad songs possible. Using the same tuning, I can also play mildly bluesy songs.

I can also tune in D-A-G and play minor songs.

Others play in D-A-C, but I haven't even explored that tuning yet.

I agree that it not an instrument loud enough for ensembles, but it provides plenty of variation and pleasure in a quiet environment. I have a list of over 165 songs that I play on so-called Appalalchian dulcimer, ranging from Salve Regina to 'Since I Met You Baby.'

As for 'tinny buzz-and-twang,' you probably have not heard good instruments.