It would be amazing if customization would allow for creation of many uniquely-looking warriors on the battlefield, so that after taking one glance at them you could identify individual players, rivals, friends, etc. people you played with or against. That's the whole point why the real knights during the Middle Ages' period tried to distinguish themselves on the battlefield. Another reason is the Rule of (Looking) Cool.
What I am afraid of is that we will end up with a very small pool of items/crests/colors to pick from, resulting in people looking similarly to each other. Since it's a lot of work to create assets only for visual effect I can imagine customization having fairly low priority over the other aspects of the game, which would be understandable approach but disappointing nevertheless.
I'm trying to highlight the benifits of optional decorations on player helms, things like horns, roman brush ornaments, tassels(feathered or cottony), coins, spikes/thorns, and other such ornaments can be applied to all three factions helmets. Which is why I believe it to be a good investment.