You should have a look at the code of the Open.Theremin project, though. There is a kind of pitch linearization, not 100%, but greatly improving the playability.
And I'd normally expect someone to become a good precision player first, then to play and to study a maximum of different actual and historic Theremin models, to get the needed musical and technical experience, before they start developing a new instrument.
I've seen ways too much theremin circuits in the last ten years which were engineered in a brilliant manner, having impressive technical data and features, but which were rapidly disqualified as unplayable by renowned classic thereminists. And the cause was always the same : The designers were good engineers but bad or no thereminists at all, so they did their designs completely apart from the needs of the player.
Remember that Clara Rockmore already disqualified the Etherwave prototype presented by Robert Moog himself to her as a "too nervous toy".