I agree with others that the concept of "mega threads" are fundamentally broken and not something I'm interested in carrying over from Reddit.
This is a place for discussion where users vote to decide what rises or stays obscure. Let the system work how it is designed. If there are too many posts about a particular topic, it's either extremely relevant at the time or there are other moderation rules that could be considered to make sure low-effort posts are not dominating more substantial posts.