Our organization has a number of Scrum teams working on various projects. Some exhibit much higher velocity than others. Unfortunately, some of the teams with low velocity run the risk of not being able to complete high priority work items in the product backlog. Management is considering whether to replace team members with more experienced and/or skilled members. For example, replacing a mid-level developer with a more senior developer. However, some believe the team is understaffed and that we should add more team members. As consultant coaches, what are some things we should consider? How should we advise our client?