Yoshiaki Koizumi

From the Super Mario Wiki

Yoshiaki Koizumi is the director of Super Mario Sunshine, Donkey Kong: Jungle Beat and Super Mario Galaxy. He also worked in other major Mario games (however not as the director).

[edit] Nintendo Power Interview

Nintendo Power interviewed Yoshiaki in a special section mainly for Super Mario Galaxy. In the interview, he revealed the following facts about the development of the game:

Yoshiaki had wanted to always create a boss fight in which the character had to climb up on top of the boss. He tried to create Ganondorf this way in The Legend of Zelda: Ocarina of Time but decided the fight would be too difficult. Later, in Super Mario Galaxy, he was able to try this concept again with the boss Megaleg.
Yoshiaki wanted to create more missions in which Luigi had to be found by Mario, but ran out of time and scrapped them.
Yoshiaki was the writer of Rosalina's Storybook in Galaxy. He wrote the story at night, without anybody knowing what he was doing. The following day, he presented the story to Shigeru Miyamoto, who was surpried when Yoshiaki told him nobody knew about it.
- Yoshiaki also states that he would like Rosalina's story to be made into a real children's book.