Is class useful today? If not, maybe omit it?

If you do need it, I think we should give BlueprintImplementation classes a type constant and use that instead -- e.g., drydock.workingcopy instead of DrydockWorkingCopyBlueprintImplementation as the thing that clients deal with. In the past, we did more "just use the class name" stuff since it seemed like a waste of effort and like code duplication to define constants, but have generally moved away from that for several reasons:

• class names are cumbersome identifiers for humans (moreso if/when we run into PHP namespaces);
• in practice, we rename classes with some frequency (T5655), and when changes occur, remapping bare class names is super confusing but migrating them is a pain;
• PhutilClassMapQuery introduced some tools to make using string identifiers easier.