Strongly against it.
First of all, as MMO player, I totally hate Discord, and it will never mean the same as TS or Ventrilo. First of all, it tries to be everything from voice-chat to chat to newsfeed, and failing at all. And also, just so you know, that crap-app collects information about what you play. I am not interested it letting it know that.
But that point actually means nothing here. However, I don't like this idea for same reason I never liked it when people linked fucking tinychat back in the day. Trying to get people join that will take activity off the chat. It's pretty much taking CL userbase and drawing it away from the site. Which is not good, and I can argue that nowadays that's semi-bannable thing. Anyways, there is literally no reason to have chat app to back up site that only has forum and chat.