Moderator meltdown over a sequel debate made me rethink our whole format

At our library book club last month we got into this huge fight about whether the sequel was better than the original. Two members almost left over it and the moderator actually shut down the meeting 20 minutes early. That night I realized our group just picks books and lets anyone talk without any structure. We've been meeting for like 3 years and always have the same 4 people dominate. So I drafted a simple rule sheet with timed turns and a "no spoilers past chapter 10" rule. We tested it this week on a mystery novel and it worked way better. Has anyone else had to overhaul their club's discussion rules after a painful night?