Thank you for all the replies.
I just read what was discussed in the link below and all my questions have been resolved.
I think removed features will eventually be implemented and developed somehow by someone. So I think this will be a loss for everyone. Of course I will follow Twitch’s policy as much as possible so it is not me who will develop removed features.
Since all the discussion has been done enough in the link above, I think no further discussion is needed here. Thank you again for all the answers.
