I think the main reason yelling "fire" and the like are illegal is that such speech is intended to and does cause action on the part of others. Solicitation to commit murder, inciting a riot, making a false report of a crime, uttering a forged instrument and making (credible) verbal threats are illegal for the same reason. None of these are illegal because of the lack of opportunity for analysis or debate, but because of the direct link between speech and action.
Those are in a whole different class than I was thinking of. Those are with the express intent to further a crime. Although I guess the Fire example can fit there too, although I was thinking more of someone who thought it would be funny, but not necessarily anticipate the full breadth of consequences.
The issue though isn't a link between speech and action (PE coaches don't violate this although their barks usually directly create action). It's the link between speech and furthering a specific crime.
