I found a very interesting article from a Dutch newspaper, containing a review of Leon Theremin, playing in Paris in December, 1927. The article provides a wonderful image of the impression that Leon Theremin and his new instrument made on his audience.

It's very obvious that the author is very excited about this new instrument. After giving a very detailed description of the technique of the Theremin, he comes to the conclusion that Theremin's approach has only one weak point: he tries to imitate the timbre of existing classical instruments. This (according to the author) leaves no room for innovation.
Nowadays, nearly a century later, this discussion still exists. In my honest opinion this topic is far less relevant as is was in 1927. The Theremin has served as a blueprint for the synthesizer and all electronic instruments after that and has earned its place in musical history. As a musical instrument it is however still in the same stage of development as it was back then: the only difference is that the technique is now digital instead of analogue. Even though the Theremin will hopefully be improved in the future, one shouldn't exaggerate the uniqueness of the instrument.
The only thing that truly sets the Theremin apart from other instruments, is that you play it without touching it. For the rest, it's the same as any other instrument: just another voice to make music with.

For a full translation of the article, click here.