In current situation, we cannot create custom processes in request and change management (Actually we can in change but it's defined as a defect).
Different business units with different business requirements are using SMAX and managing all this requirements in same OOB processes is getting harder over time. Offerings and models helps on this issue but some business rules are required to be run on process-level.
Additionally, phase and transition additions make workflows less understandable.
It would be great if you take this idea into consideration.