Lookup User by Display Name
Add a "/users"-like API method that supports display names. This will let bot commands which have a username parameter support Asian-family character display names to be passed the same as Roman-alphabet channel names. It will also let systems verify that a provided name (channel or display) exists on Twitch, and merge any information for a user's display name with the information for that user's channel name, to prevent "duplicate" sets of data: one for the display name; one for the channel name.
Providing info only if the user is @tagged would require any commands such as "!so" to require an "@" instead of it being optional, but it would have the added bonus of not requiring an API call to look up the right name. I can see potential use cases for both methods.
What about a tagged-users array that shows info about all the tagged users in a message like discord