It would be very usefull to have posibility to define custom roles like 'Developer Leader', 'Test Leader', 'Analyze Leader' etc.
Then the next, it would be necessery to implement wokflow vaildators and conditions which could use it.

Having such a feature, would be very ease to create really great worklflow in wich I could define auto update of asignee field.
Now I may definine it too, but I have to set asignee 'by name', When developer leader is changing or is absent I have to change workflow.
Using such a roles I would only change roles.