I don't think there's any need to bundle IM and IRC in the same package. Just means unnecessary bloating.
Smileys look pretty, but they don't serve any useful purpose, as I find most of the extra features on IM's.
mIRC already has file transfers added to it. That's useful.
Only other feature I think would be useful to add would be a status system and away system that works more efficently than the notify list and away messages, like I described.
I might script such a thing myself some time. and see how it goes and if it catches on.