Make document approval workflow similar to process approval workflow

We have the document approval workflow (DAW) turned on. The current logic behind DAW is that document approvers are either the process group owners or (if there are no process group owners) the Promaster. Our process group structure does not lend itself neatly to having process group owners. Currently, our options are to add process group owners to process groups where they don't truly have accountability (not really an option), or have Promasters approve documents that they don't truly have accountability over either. We suggest the ability to set document approvers at the document level (not process group level).