I believe that TESO will provide and interesting chance for heraldry to be used for stylistic and practical purposes . . .
Imagine a PvP scenario and you want to signal to your comrads that a certain part of the castle has been secured and an Aldmeri soldier plants a flag with a yellow glow around it for others to see and rally to. (Alternatively red glow for Ebonheart and blue glow for Daggerfall).
My idea is that in Cyrodil the battle standards for each of the faction alliances will be used as signals to rally more troops.
Outside Cyrodil, it may be interesting for players to be able to unlock or create different sigils and banners through achievements and/or crafting? And what about Guild tabards and banners and such? Have we heard anything about these sort of aesthetic embellishments?