Modular and configurable bootstrap
The bootstrap contains a big amount of specific initialization methods. The order of execution and selection of initialization methods is hardwired in the Bootstrap class. This makes it impossible for package developers to provide alternative boot sequences for specific tasks (such as for a very optimized caching mechanism) and in general results in a rather function-based, sequential code than being object-oriented.
It thus should be possible to register Request Handlers for specific purposes and those should be in charge of the actual boot sequence which is executed.