I'm not sure what you mean. Do you mean the role class itself,  or the association with puppet class? This is for the "default" roles (config, controller, etc) -- we're associating them with puppet clases, etc. -- which will be copied over to the HostGroup at deploy time. 

Longer term, I've discussed with jay and morazi that we might want to refactor this post-April into an actual HostGroup -- but we'd need to extend it in the engine in that case with the associations with Services, Layouts, etc. Anyway, we're aware of possible duplication here and hopefully can hammer out a longer-term model that reduces it, but at this exact moment, I don't have any more time for major revisions to the object types, etc. given the schedule.