I wonder if it would be interesting if Square Enix tried to do one better than World of Warcraft in one thing:

Facial/body animations during /say dialogue with other players.

When you type and talk in WoW, your character animates according to the dialogue, though it is straightforward.

If Square-Enix could somehow implement a context-sensitive version of the dialogue where using exclamation points or questions, or even pointed statements would result in a different kind of animation.

An example is this:

"What's going on?" (Resultant Animation for Miqo'te: Cocking the head to one side in curious wonder)

"Oh, what the hell are you doing!?" (Resultant animation for most characters: Angry expression.)

Also, lip synching would be applicable here, too. Kind of like how the NPCs lip-synch their basic dialogue in cutscenes. That should be applied to player characters.

The whole point of this is to make your characters seem more animated and part of the world, rather than a stone pillar of unspeakingness.