The phrase "much discussion" means that there has been a lot of talking, debating or arguing about something. It implies that people have spent a significant amount of time discussing an issue, topic or problem and trying to come up with solutions or decisions. The word "discussion" refers to the act of exchanging ideas, opinions and arguments in order to reach a consensus or make a decision. When used together as "much discussion," it suggests that there has been a lot of back-and-forth communication, brainstorming and analysis about whatever issue is at hand.