Here's a pretty thorough pros vs cons list of discord vs IRC.
I know you guys are sold on IRC, it's tried and true and, anecdotal evidence aside, I totally understand the reasons that make IRC objectively better. But there are a lot of neat features Discord offers that picks up the slack. Obviously, the community isn't asking you to shut down your IRC channels and replace it with Discord. Just make a discord channel and let the community use it. If you guys become drawn to it as you use it, then so be it. I just don't see a reason to not give it a try.