You can fool yourself with Serviceable instead of Composable and shit like that, but the truth is: many many many times
Generator file = new FileGenerator(src,handler,parameters);
would have been enough!!
Well you refer to some overcomponentization in Cocoon, but Generator is not the place where it is happening. More like XML compiler/decompiler, which might be simple class instead of component.
And in other places we have undercomponentization as well, example is [Image|MP3|*]DirectoryGenerator, where you need pluggable file introspection helpers.
Vadim
