As stated, entirely cosmetic, but I noticed something new when my characters proc the Frenzy Tap given by Aura of the Frenzy. There's an emote that happens now as well, "*character* beams a smile at *target*".
Only reason I even noticed it, since I've got emotes set to a spam window, is that the giants in Kael were extremely chatty while they were getting beat up. Every time the proc would go off and the emote would happen, they'd go yelling back "I'll teach you to interfere with me *character*!"
So, apparently, Kael giants don't like being smiled at, who knew...