I think that many would agree that half the fun of this amazing game is the customization and roleplay aspect and it would be great if we could get more options in the way of player customization in PvE and PvP. The Mark VIII and Mark X Phobos are what I'd like to see most but there's so much more that could be added over time to really enhance the player customization experience.

The MK VIII Errant Helmet is already in the game, there's the one with the Raven Wing symbol from the Dark Angels cosmetic pack and they released one without the symbol during a community event a few months back. As for the MK X Phobos, 100% agree this needs to be added in the game, at least the full helmet cuz we already have the half mask for both the Vanguard and Sniper classes.