Adam wrote: "I think when I am watching many of these youtube guys they don't know what the note is they are aiming for in the first place...."
You are absolutely right, Adam. This is particularly true with people who are playing classical pieces by ear. They often do not know what the notes are, and they are playing "by the seat of their pants". This is fine if your audience doesn't know the notes either, and this is frequently the reason why people who play rather badly are hailed as BRILLIANT.
Theremin player and teacher, Kip Rosser, posted a video recently - "A TIP ABOUT READING MUSIC" - in which he pointed out that no matter how well you think you know the notes of a classical piece you love, if you check them against the written score you will inevitably discover you are making mistakes you were unaware of. This is one of the rare times I agree with Professor Rosser.
Adam continued: "The Talking Machine...It sounds really cool although I think if you did a whole album or concert with it, it would become like Frampton Comes Alive after a while..."
This is true of the theremin in general. The instrument, as remarkable as it may be when it is played well, is a "one trick pony", and once you have done that trick a couple of times it becomes tedious. I think this is one of the reasons that Clara Rockmore, when she shared the stage with other artists (such as bass baritone Paul Robeson), instead of playing the entire first half of the show like an "opening act", would alternate after each composition, back & forth, with the headliner.
The pony's one trick works better if you interrupt with a chuck wagon race every few minutes.
The problem boils down to the fact that the expressive capabilities of the theremin are severely limited when compared to the human voice or other monophonic instruments. It cannot change timbre, it sounds vaguely vocal but it cannot express lyrics, it cannot play connected notes that are separated by much more than a fourth, and it isn't capable of a true "staccato" or attack. It has no repertoire of its own beyond some rather obscure compositions by little-known composers and even those pieces require a level of virtuosity that only a tiny handful of thereminists have attained.
All this sounds rather negative, but I think it is realistic.
There is a contingent of theremin supporters that has always maintained that "the theremin is limited only by your own imagination!"
This level of enthusiasm is admirable, but these people are wrong. The instrument has many inherent limitations that no degree of imagination, no matter how creative or zany it may be, is going to be able to overcome.
As someone once said of the elephant ballet, "It is not the beauty of the dance that enchants us but the fact that the great beasts can do it at all."