Many big streamers have hundreds of emotes in their default emote set. If the moderators or the streamer want to copy the entire emote set and replace specific emotes with themed emotes such as the Christmas emotes, that functionality isn't present today and will be very helpful. As a bonus, if we can multi-select emotes within an emote set (select all/select none/invert selection, etc.), it will allow us to import them into other emote sets, allowing us to play around with emote sets much more freely.
From an implementation standpoint, a subset of an emote set and an emote set itself can be represented as a set of emote IDs (not emote names) as simple as a comma-separated string. Would much appreciate it if this functionality could be implemented soon 🙂