The Legend of Zelda: Wind Waker 2 was the intended sequel to Wind Waker, according to a report on Nintendo Everything. In an interview to be published in upcoming art book The Legend of Zelda: Arts & Artifacts, Nintendo artist Satoru Takizawa explains that the game was originally designed to take place on land, not water.
“To tell you the truth, we had begun the initial steps towards creating Wind Waker 2 around that time. However, demand for a more Ocarina-like game was growing by the day. We did our very best with Wind Waker, and put everything we had into it.”
Nintendo also had plans for link to be able to ride on a horse, presumably Epona, but this was another feature that got canned:
“Link’s proportions in Wind Waker weren’t very well suited for riding on horseback, he was too short, and an adult version of Toon Link did not seem appropriate either. So, while we were stuck on those problems, we became aware of the greater demand for a more realistic, taller Link. High-budget live-action fantasy movies were also huge at the time, so with all things considered, we decided to have at it. I was on board with the project as art director, and started off by bringing [Yusuke] Nakano on to do the design for Link.”
As a result, the realistically proportioned Link ended up in The Legend of Zelda: Twilight Princess. The Legend of Zelda: Arts & Artifacts will release in February 2017. It is already available in Japan.