To be a formal debate, the debate must include set rules and guidelines. The teacher or the person who is in charge of the debate should make clear rules and guidelines about what is permitted and what is not in a debate if it is to be a formal one. It doesn't have to include strong opinions if it's a formal debate only - any type of a debate should have that. Personal attacks are not necessary for any debate, as is unlimited time to talk. However, rules and regulations are indeed important.
