The people over at ELiTeD tossed up an interview with the Raven Shield team, Chadi Lebbos: Producer, Mike McCoy: Lead Designer, and Eric Begin: Lead Programmer. Here is a clip from it:

Will there be smarter AI than past Rainbow Six games?

Absolutely! We've put a lot of effort into all aspects of the AI. Your teammates work with you to cover your flanks and accomplish the mission. Terrorists work together as a team to defeat you. Finally, hostages react to being rescued and the anticipation of gunfire.