Didn’t New York City Ballet’s fall season, which ended Sunday, feel like a whirlwind? As the company passes the baton over to American Ballet Theater — the David H. Koch Theater is home to both companies this fall — it’s a good time to take stock of what left an imprint. The happiest sight was the debut of Mira Nadon in George Balanchine’s “Rubies.” The most distressing was the return of Marc Happel’s costumes for Balanchine’s “Tchaikovsky Piano Concerto No. 2” (1941).

Costumes may not seem like the most important part of a ballet, but they can alter its mood. While the new costumes — blue and sparkly, with horrible vests for the men that make them look like they should be lifting hotel bagga ge, n ot ballerinas — were unveiled last winter, seeing them again was disheartening. With their 1980s vibe, they make the ballet hard to watch, and that’s terrible because it’s a beauty of a dance. It’s also grand. In 1973, Balanchine simplified the décor and costumes with the thought that the ballet didn’t need anything extra. I miss the old chiffon skirts : simple, clean, elegant. Now we have thousands of Swarovski crystals; it’s Disney-princess time.

Costumes aside, in that ballet and in others, Russell Janzen showed why he has become an indispensable member of the company. Tall and elegant with a gentle demeanor that places the woman first while never fading into the background, Mr. Janzen has found a new breadth in his dancing, which is deliberate and wholly noble. He is also forging a remarkable partnership with Sara Mearns. The way they dance with and not at each other — especially in Balanchine’s “Diamonds” — creates the sort of luster that makes you forget about steps.