For Eldar it would be 10k RTC PER CLASS ^^^ No matter how much I would love an Helmet-less Eldar (wouldn't change the TTK all that much), then I would still prefer getting Jetbikes/Bikes (including Vyper Jetbikes and all that), Vehicle Customization, TEQs, Wraithblades/"Melee TEQs" (won't be in the first version of TEQs), Combi-Weapons (for Orkz, LSM and CSM) and my bloody Looted 'Umie Bolter and Wyrmfang Spear. I know the Relic Weapons aren't high priority due to how small a base of the players who would benefit from it (the Golden Fixa still isn't fixed for an example), but the other stuff might bring more players to the game.
It was never meant to have any gameplay implications, as it is a cosmetic choice. The hold-up is due to the animation and rigging it would require, which is currently unsupported and they don't want to just have the faces be inanimate. The mask is for all Aspect Warriors a symbolic item of spiritual significance, not a practical one. Both the Mandiblasters and the Sonic Amplifiers can be used without it, attached to the head as such:
Just wait for it to happen and then see the miniature heads that the models have...the helms now are as big as the heads inside should be, with the exception or Orks, since they have their face out in the open already.
Space Marines being all erached by microcephalia i would say that without helmet headshots will become far more difficult to make.
Back when I last heard them speak about the "no helmet" option they said you would take extra damage, but it sounded like you would also get some other benefits (can't remember what).
This^ because I am sick and tired of space marines (and sometimes really retarded eldar) running around helmet-less and somehow not getting shot in the face in the lore. That would be my first instinct. Chapter masters be like View: https://www.youtube.com/watch?v=5mNzMLnfuig Your face........ but covered in golden glitter...... wait a second........ Dante? is that you? 100% agree at the end of the day this is a cosmetic and should be prioritized as such: BELOW real game content.