Super Mario Bros. Wonder contains all sorts of hidden secrets and surprises, but there were also a lot of ideas left on the cutting room floor.
As highlighted by producer Takashi Tezuka during a chat with Famitsu last week, there was a point during the game's development when the team considered Yoshi's egg-throwing mechanic. Ultimately, the concept "became hard to control" and Nintendo didn't want to isolate new players.
Here's the full translation, courtesy of Nintendo Everything:
“As for Yoshi’s actions, I thought it would be better if he could throw eggs, so we tried to create a prototype and test it. However, it became hard to control, and to let first-time-players have fun, we decided the current way was the best.”
Egg-throwing mechanics have previously been seen in games like Yoshi's Island and Yoshi's Story. In Mario Wonder, Yoshi ended up becoming one of the characters who doesn't take damage when hit, but also can't use power-ups like other members of the Mario crew.