I recall RDJ only being signed to 4 pictures (IM, IM2, IM3, and Avengers). So do you think he'll stick around for more after IM3? And if not, who the hell could possibly replace Downey?!
Phase 1 >>> IM - TIH - IM2 - Thor - CA: TFA - The Avengers
Phase 2 >>> IM3 - Thor: TDW - Captain America: TWS - Guardians of the Galaxy - Avengers: Age of Ultron - Agents of SHIELD
Phase 3 >>> Ant-Man - Doctor Strange