I think that a good idea to do are private streams, or streams that can be joined only with a code/invite (i’m not sure if it exists already) it would be cool if you just want to share gameplay with a friend but ur not on pc
Feature requests should be submitted on UserVoice https://twitch.uservoice.com/
There may already be a suggestion for what you’re after so if there is make sure to vote for it so Twitch can see what sort of interest there is in such a feature.