Solve chat spam: Use chat groups and comment-upvotes as a filter
Too many messages in chat make the stream spammy and makes it hard for streamers to see what is going on.
It also makes it hard for viewers to hold conversations with each-other or even follow what is happening.
If viewers could stay in smaller chat groups, they could hold actual conversations in those groups.
And if those groups could upvote comments, the most-voted comments could be made visible for all users in every group, working like a spam filter in which only the good comments are made visible for everyone, reducing spam drastically.
Imagine it like going to watch a movie with a group of strangers, talking about things between yourselves, while the top-voted messages get sent to a bigger audience (and the streamer) to interact with.