What’s wrong with IRC? It’s just another method that’s used to exchange the peer list. You can just prevent it from connecting and use -addnode=1.2.3.4 to connect to a known node for bootstrapping if you want..
If nodes disconnect from IRC after they get their list then it makes it less useful for bootstrapping since it will be empty except for the node that’s trying to bootstrap at the time.
IRC has been around forever and it’s well documented (and easy to understand for newcomers) - why create something more complicated?