I don’t quite understand the problem you are having. If a streamer misses a subscription there will still be the USERNOTICE event if the sub chooses to share it, so all overlays and alerts that are triggered by such subscriptions will still go off even if the streamer isn’t reading chat. To have alerts for even the people who may not want it announced that they just subscribed it is still possible to see new subs by polling the subscribers endpoint and looking for changes. From my view, I can only see it adding value to viewers as it gives them the option if it is to trigger an alert or not, much like resubbing, and twitchnotify has it’s own issues so I’m happy to see it gone. The only people that might have issues are those who have bots that track subs but the channel owner hasn’t given OAuth permissions to access the subscriptions endpoint, in which case those bots will now miss some subs but those people should never have expected gathering sub data in that way to be reliable or to always continue in that way.
Maybe I’m missing some other downside to twitchnotify being removed though, and feel free to correct me if there is as I’m curious why this is anything but a good thing?