We currently have no plans to move away from IRC for normal channel communication. The IRC protocol has been proven to be a solid framework for group communication. Websockets is merely a different transport protocol underneath the IRC application protocol, making it easier to communicate from a browser context.
However, there are a number of features that we want for user<->user communication that the IRC protocol fails to provide. Therefore there are plans to move whispers (and only whispers) to a different system/protocol that better suits our needs. I expect we’ll announce more details about these plans as they approach completion.