In Letter II, Jean speaks of a list of topics pertaining to the ballet performance, firstly, the characteristics a ballerina should possess - may he or she be a maitres de ballet or part of the corps de ballet - secondly, the makings of a good ballet performance, and in Letter IV, he says that ballets of the later age in his time (it being the 18th century) are too clouded by complicated steps so that the basis of ballet is forgotten; its importance seemingly having taken a backseat.
Ballet was a dance performed strictly for royalty in the 18th century, the time which this article was written. It was a platform for the nobles to show their social status, and one's elegance and poise could be shown through the dance. Noverre complaints about the maitres de ballets who have an air about themselves and believe that the other dancers in the corps de ballet should look up to them; to use them as models, and how wrong they are in this mentality. In ballet, or any other dance for the matter, the primary focus is for it to tell a story; evoke an emotion of some sort in the audience through the medium of movement. This is an unchanging fact of dance which Noverre points out, relevant from the 18th century till now, the 21st century. In his letter, he points that a performer needs to practice humility, the art of staying humble and never allowing fame to get into one's head. As mentioned earlier, the dance is meant to be a show of elegance, poise and the worthiness of being in the aristocratic class. This is relevant in ballet today, as ballerinas are still required to perform passions, manners, customs and ceremonies, and in order to achieve the "moment of expression innate in mankind", one must stay humble and never allow oneself to be complacent.
In the 18th century, there was a heavy emphasis placed on grandeur sets, huge costumes and gigantic head-dresses which were to show off the wealth and give an air of nobility while performing for the king. However, being ahead of his time, Noverre had the vision of removing such cumbersome items so as to not distract the dancer from the main focus of the ballet - the expression and the elegance of the steps. "renounce cabrioles, entrechats and over-complicated steps...discard the use of those stiff and cumbersome hoops which detract from the beauties of execution". His thoughts are very much alike the modern ballet which are constantly being performed today, whereby dancers strip to the bare leotard, taking away the heavy costumes so as to allow freedom of movement and not to distract the audience from the facial and bodily expressions; the grace of simple steps rather than a medley of grand jetes which might look impressive, yet holding nothing to the foundations of ballet. Each member of the ballet is as important as the next, hence there is no one point in time whereby one dancer should feel more important than the next.
Also, Noverre touches on the topic of the dance itself. It must be of entertainment value, yet more importantly, it must tell of a story; in his own words, an "introduction, plot and climax". However, in modern ballets, not all performances have a storyline, but merely to showcase a culture, a message which the choreographer wants to share with the audiences. Most of the ballets which still follows that structure are the remakes of the old stories such as La Sylphides, Swan Lake, Romeo and Juliet, Giselle and so on.
From the content of his letters and his direct manner of speech, he is obviously terribly modern in his ideas and his concepts of ballet, which are still relevant up till today.