I very much understand your sentiment, the voice encryption had been made optional because of the cpu load it generates. Since the ts3server is still being used on sometimes rather weak hardware, i do not think we can remove disabling the voice encryption. What i think that is realistic is that we can change the defaults for new servers, so that voice encryption is being enabled per default going forward.
For that i will have to talk with a few people internally if they are okay with it, so no promises 
