Argghhh lame.
Would have been better if they were tied to some super hard challenge.
They are! You think you'll just unlock them by getting the gear for every specialist? That's not how it works. Unlocking the gear for every single specialist only unlocks the requirements to obtain the hero gear (which are super hard). For example, to get Nomad's hero headpiece, you need to get six kills with the HIVE in a single game six times.
-TGM