Considering that everybody else, including the snowman, gets a fully orchestrated musical number, it does seem like Jonathan Groff got a little short changed here. He’s had a bit more opportunity to sing in the followup shorts, Frozen Fever and Olaf’s Frozen Adventure, but even then, he hasn’t had a chance to break out with a big Disney style song.
Article source: https://www.cinemablend.com/news/2478927/frozen-iis-kristen-bell-shares-her-one-critique-from-the-original