While I can't speak on the books having not read them and what I have heard of them seems to contradict itself (seems to be a lot of that in WH40K. Also retcons. also favoring the main race.). Here's my understanding on helmet and "War Mask". Take this previous image, focus your attention on the Exarchs head. See the things to the side of her face? That's where the damaging scream comes from and that's what offers protection from their screams. Along with the fact it's focus is directed forward. Now take what we know about Eldar function of weapons. Activated with their minds they are (Astartes "Black Carapace" can more or less do this too). The user without a facemask portion of the helmet can still use the tech that makes the Howling Banshees scream so feared. Mandatory facemask to use their scream seems silly. What if their visor is damaged and have to take it off to continue fighting, are they then not able to use their signature strategic device? Activating it can change as war times go, weapon builders change designs to adapt and improve, and going on what @Zavalus said in post #271 that is likely. Especially for Eldar with advanced crafting, tech and such dedicated warriors. As for the "War Mask" springing up again. I see it as a mental state taken on by an individual or group by ceremony/ritual (something like meditation or hypnotism) which is reinforced by their fellow aspect warriors, aspect armor, and an Exarch. It being mental state and a helmet being a small piece of the armor set I don't see that as being necessary. Since there's still the rest of the armor, the mental state still going, and (if still alive) the group and Exarch. Again referring to "what if during battle they have to take off the facemask for _ reason?" Once taken off would they immediately not be in that "War Mask" or would it wear off? Such a notion, for a race with such formidable mental capabilities as Eldar do, seems silly. I intend to play with my helmet on sometimes, especially as banshee because they have the coolest one, but other times with helmet off. "Why?" some may ask in a belligerent manner. Because I can and want to. Altansar won't apparently. In a MMOTPSRPG. "It ruins my immersion!" another may say in a disgusted tone. I can promise that in-game you won't give a lamb about what I am or not wearing. Also not having the option to go without helmet in fighting scenarios ruins my immersion. GW models are shown helmetless. Join the Path of Fashion! It is inevitable. Join usssssss. "What if going without helmet means taking addition damage?" others would ask in a shocked tone. Hahahaha! Oh that was a serious question. *ahem* So what? In Eternal Crusade myself, you the reader and everyone will die. Repeatedly. I have played games before. It's more common than others would lead you to believe with stories of their "awesome plays". So common in fact I think it should be in the tutorial for the game. It's not like a helmet will guarantee immortality either, with all the horrible ways to die on Arkhona there will be. Even headshots with a helmet are are capable of putting pain into our souls (cookie for anyone who knows that pain reference). It won't be the first time I've done something foolish for the sake of cool/enjoyment in a game. I play Fashion Souls (Dark Souls; action RPG). I'll quote an exchange between Thor and Heimdal in Marvel's Thor (2011) movie, take it however you wish I found it amusing: Thor, no helmet: "I have no plans to die today." Heimdal, yes helmet: "None do."
As others have said things like gems and shrine markings will make great non lroe breaking cosmetics and could function like decals. The other could be different colour schemes for aspect warriors as different shrines will have some variance in colour. Also the shrines according to the codex have subtle but significant differences (atleast to an eldar ) in their equipment and training, so different helmet/armour shapes could be feasibly included.
Apart from the color of the armor/armor customization, then there is the color scheme of our weaponry. So far there seems to be only one confirmed weapon (for Eldar at least), which we could call a "unique" color, the Ice Hawk Cannon (Shuriken Cannon in winter pattern). Do anyone here know whether or not the markings on the weapons will change to fit the wielders faction? If I equip the Ice Hawk Cannon as a Iyanden Dark Reaper, will the Biel-Tan mark then change? Or is the gun locked, so that only Biel-Tan can equip it (this would seem highly unlikely)? Btw, why is everyone starting to wield a moustache? EDIT: I donned my moustache the 7th of June 2014
Yeah RTS stuff change to match your sub-faction. Markings do anyway. I don't know about the color scheme. Only reason I can give is because Eldar Artwork thread had a mustache phase. It was nice.
best arguement for the inclusion of the helmless option apart from Rikamars points is a recently obvious one ... "Altansar Elder never remove their helmets" why would that fact need to pointed out if none of the craftworld elder ever removed their helmets? and more importantly .... do the Altansarii all wear helmets all the time? even when they are by themselves without strangers around? all of them including guardians and farseers and civilians etc?
Because you are not at war all the time. Altansar don't ever take their helmets off, even under duress, hence why they're held in suspicion by other Eldar. So if Altansar do make it as the 5th craftworld, that's yet another reason not to have helmetless options.
Yeah the whole helmet thing would make Altansar a rather impractical choice, then again it was the devs who made Altansar a choice in the first place.