No it wasn't.
Their stated reason for the lack of headgear was that due to their unique designs, the new races would not be able to wear hats. As they put it, the choice was to either compromise on the character designs OR make them as envisaged but unable to equip hats.
It's not simply a matter of backlog. It's a design decision - whether sensible or not - that will continue to carry forward. They will be able to equip masks and circlets but there are not and never have been any promises on actual hats.
Refer to the last section of
this Letter from the Producer. "Due to the special design of the Hrothgar and Viera heads, equipped headgear would not display".