The reasoning is that we will distribute two types of bundles: an "angular2" bundle, and stripped down "sub bundles." The angular2 bundle that will include all "sub-bundles" like core, forms, http, router, web_workers, and there will be a version of the angular2 bundle that includes third-party dependencies like RxJS, reflect-metadata, polyfills, etc. The separate bundles, for more advanced users, will then not include any dependencies, and assume that dependencies have been provided elsewhere.