I'm currently working on a team of data architects. We usually agree quickly on a given design for most problems, but occassionally we do not. When there is disagreement, the question becomes whose design wins? How should we determine the "winning" design? If the debate drags on too long the team's velocity comes to a crawl.
In other situations there is a designated "lead architect" whose design approach may not match what most other team members feel is correct. But again, on-going debate causes velocity to suffer, tensions to flare, etc. How do you solve these issues?