The "new music" only applies to the English and is an attempt (and I stress the word attempt) to make the English translations fit better to the traditional prostopinije melodies. When the liturgy was first translated into English 40 years ago, the rule of thumb re: the music was to keep it simple. The new rule of thumb, apparently, is to try to complicate, for lack of a better word, the melodies, bringing them closer to the original Slavonic. In some cases it works well; in others, it doesn't work at all. IMHO, I think the times that the new music has failed (to my ear) is largely due to poor translation (not necessarily anything heretical, just "bad English") and an attempt to make the words fit the music instead of the other way around.