I don't mind the default facial expression...but we having a "mood sign" (it's super-duper gay...i know...no need to tell me this) at enemy and ally sign menu, where we could set a temporary mood to our character until you cancel or enter in active mode (no one will fight in shy or happy expression so i do think it should be canceled when we go in active mode).

What a mood sign would do: Change your character facial expression to the chosen one and add a mood bubble on your character whie the mood sign is active.

I also would love seeing facial emotes, like showing tongue, blushing, grinning, smirking, raising only one eyebrow for disbelief expression, etc.