Chat Control / Reducing Chat Volume
Create a separate chat channel that only allows only 10 comments to be posted a minute (or something similar), with an added chat queue system. If I type a comment, I will have to wait in a queue for my comment to be posted, as only a certain amount of comments will be posted to the chat within a timeframe.
This will make it so a chat channel exists without a crazy amount of comment volume. It will allow streamers to actually see and read comments people are making. Yes, it does mean a lot of comments won't be posted, but this will simply be a feature of this specific chat channel. It will deter spammers because the comments you make become more valuable. The main use of this channel will be to simply reduce the volume of comments in chat.
Perhaps instead of their being a separate chat channel, allow streamers themselves to set the limit of comments per minute.