It's all variations on IRC. I'd think something resembling Google Hangouts for the audio/video aspects of Discord, with threaded IRC with history for the text c

It's all variations on IRC. I'd think something resembling Google Hangouts for the audio/video aspects of Discord, with threaded IRC with history for the text chats would almost completely cover all use cases. A Discord-like client would join the two services under a single interface and identify the user with a service-appropriate identity.