The Nintendo Direct presentation that focused entirely on Pokémon has been removed from Nintendo’s official YouTube channels in North America and Japan. The company has also pulled the Pokémon Sun and Moon reveal trailer, which was released around the same time as the Pokémon Direct. Apparently, Nintendo typically removes videos when there is a possibility that an enhanced version of the game in question could potentially be in the works. Is this directly related to the rumored Pokémon Stars? Many fans appear to think it does.
Source: NeoGAF
Pokémon Blog 