When someone sees fanfare because of a subscription, and they’re new to twitch, so they decide to subscribe, and nothing happens – that’s bad.
The last time we did a main stream we had almost 20 new subs come over from facebook livestream before the stream even started on twitch because of the fanfare we were able to produce. When we pre-streamed on the 15th we reached 480,948 people on facebook - don’t tell me that people who are new to twitch are insignificant or don’t matter somehow 
WRT “Privacy” - that’s a non-issue. It affects an extremely tiny proportion of the twitch population, AND the option to lurksub already exists in all the ways that have been already mentioned.
Really? You’re complaining about Japanese characters? Compared to the number of hoops you’ll have to jump through to poll the API for new subs who don’t know they have to announce, that’s another non-issue for the vast majority of streamers (especially when IRC twitchnotify returns roman chacters).