Remote Play, the ability for PS4 games to be played on the PlayStation Vita, has been confirmed as a mandatory requirement for all PS4 games. The only exception is for PS4 games that require hardware such as the PS4 Eye.
The Wii U has a similar feature with it's gamepad allowing gamers to play their games away from the TV. However, that feature has mostly been optional for Wii U developers to implement. With Remote Play enabled for the majority of PS4 games, this could noticeably increase the sales of the struggling PS Vita and even help the PS4 at launch.
Combine this news along with Sony's stocks increasing 9 percent after the Xbox One reveal, and it looks like Sony may be off to a better start with it's console than first believed.