I was thinking about something similar, but using Telegram instead. Telegram bots can do anything you can write on a script, so I'm pretty sure it's possible to make them echo the in-game chat and respond to commands, just like in IRC.
It would be easier to set up (as simple as clicking on a link to join the chat) and use and, as many people already use Telegram, you wouldn't have to install additional software. You wouldn't need bouncers to keep you always online, Telegram always saves the messages whether you are on or offline (some bouncers are paid, and the free ones only save up to a number of lines, usually 5000). And the Android/iOS apps are way more stable, customizable... (better) than any IRC client. Also, it would be cool to have a channel you could join to receive alerts when there's an event, get updated when the server is down, to find out about the latest updates or to announce important polls going on in the forums. It would keep people more connected to the server when they can't play, in some sort of way :p
But I imagine this is quite difficult to make. I definitely have no clue how to carry it out.