DeltaV Workgroup or Domain?

Currently our DeltaV workstations are setup to login to a workgroup which will be an Administration headache once we start adding individual accounts on multiple workstations.

Would a Domain controller on the Proplus help without adding headaches in other areas such as when the domain controller is down or being worked on? 

Would changing a computer's membership from Workgroup to Domain interrupt the current DeltaV environment?