allow streamers to set a limit on the number of people that can send messages chat.
Since twitch has grown in size, many people have realized that streamers can no longer engage with their community the way they used to. Even with subscriber-only mode turned on, due to the massive increase in twitch prime subs, most long time streamers' chats are still filled with spam. You should give streamers a mode that limits the amount of viewers that can talk in chat, giving priority to those who have been subbed the longest(including or not including prime subs), and then those who has been following the longest. This gives people who have been watching a streamer for years the opportunity to engage in the community that they watch the streamer for in the first place, and gives more control to the streamer who may want a break from the relentless spamming when they are having a bad day or want to engage with their community the way they used to be able to.