Rainbow Six: Siege has a new available that walks you through some of the design decisions the development team decided to implement in order to make the game a more tactical and, more importantly, more responsive shooter.
The video is part of the Behind the Wall series, which discuss design elements of Rainbow Six: Siege. The focus of this episode is on minimising input lag, by prioritising player control over "cinematic animations" and more.
There is an interesting bit in there too about the team choosing not to have a contextual lean system, and allowing the player to change their stance anywhere instead, similar to classic tactical shooters.
Rainbow Six: Siege is out sometime in 2015 for PC, PS4 and Xbox One.