In general, role-playing games have reputations as hundred-hour monsters of unique depth compared to other genres in gaming. The Witcher 3: Wild Hunt is particularly infamous for being an intimidatingly long affair, and most stats show that many players, even though they got really far in, never saw the end of the game.
Keeping this in mind, CD Projekt Red decided to make the main storyline of Cyberpunk 2077 slightly shorter than Geralt's adventure, but there won't be less to do overall.
Senior quest designer Patrick K Mills spoke about the length of the two games on the last episode of Night City Wire, and mentioned that the team wants to 'show you the whole story'. This doesn't mean that you are getting less game, but the ratio of main story to optional side content is tweaked.
Seeing the gist of V's story will take less time than the main storyline of The Witcher 3, but there is so much additional content to explore that completionist playthroughs will be of unprecedented length.
We want you to see the whole story. So, we did shorten the main story, but we have lots to do. And in terms of a completionist campaign, I just don't have that number.
This is in keeping with another comparison to The Witcher 3. Earlier in Cyberpunk 2077's marketing cycle, CDPR revealed that the area of the game's map is smaller than the game world in The Witcher 3, but due to more interiors, greater density and verticality (this is a metropolis with towering skyscrapers) there is ultimately more world to explore.
Far be it from anyone to suggest that Wild Hunt was shallow, but it seems like in Cyberpunk 2077, CDPR is cranking up depth another notch while reining in breadth.
Cyberpunk 2077 remains on track for its November 19, 2020.