I think the sometimes bizarre combat "dialogue" is meant to be an informative indicator for the player rather than, well, dialogue. It does it's job and allows the player to see the reactions of creatures regarding the current situation in a game that can't convey most body language or expressions.
I think screaming and such could replace the current very explicit pain indicator. After all you wouldn't know if someone was in pain if they didn't show signs. Perhaps also add flavor text messages or dialog to indicate nauseation, fatigue, enragement and other combat states rather than have them presented in a simple list?
I don't think the dialog is really too informative as it is. Toady already said many of the internal dialog trees that npcs use to talk end in "it was inevitable". Meaning most of the dialog as it is seems to be placeholders. Adding in screaming lets us flesh out some of the dialog trees already in the game. Even if it is used to simply fill the fear branch of the tree with something other than "terror is all around me... begone fear!" Doing so adds more personality to the game simply by not making every character a Shakespearean villein, and also allows the player to use their own minds to fill in the gaps.
Just think of all the ways you could imagine someone screaming about something, vs the dramatic dialog present. The dramatics certainly can stay, and probably deserve their own branch (possibly in some form of in game comedy or theatrics later on in development? ). My only other request to this thread would be to make crying more visual somehow. Even if just a blue *crying* tag was appended to the end of a sentence. As currently it involves a few quirky look commands to even check if you are crying, let alone other npcs.