Lightwave has this approach (separate modeler and animation programs) and it can be a real pain, especially when working on smaller projects. I much prefer the approach taken by Carrara and C4D (everything integrated into one package). In a studio workflow where jobs are compartmentalized and some people just model all day and some just texture, light and animate all day things might be different but I don't really see Carrara being geared toward that kind of high-end studio work.