I would also like this. I'm deploying a country based group and trying to reduce the "noise" for them in the system and they see all these approval processes and have inadvertently added to a project kicking off notifications to users not in their organization. If we could manage approval processes like we do templates, portfolios, projects, etc then this would be better for us.
Several times we have had users attach approval processes that were not created for their company or group, triggering mass approval request notifications to hundreds of our users. it definitely adds to the negativity our users experience with Workfront.