I think a really cool franchise could be made out of Inception. It could be like the matrix mixed with a bit of bond/mission impossible action along with some spy thriller elements.And if they couldn't get DiCaprio to return then it could focus on the other members of the team and have the second and third film follow them around on other extraction jobs with an over arcing plot involving some sort of government conspiracy and cyber criminals and terrorists where they extract or plant ideas to prevent attacks and catch criminals etc.