Teng
17
This is most likely not an oversight, but a consequence of a more general policy. If you look at the NPC table, you will see that in almost all factions, the lower the thrall’s tier, the higher his vitality step, and therefore the higher the chance of getting a higher vitality value.
Most likely, the developers intended this to compensate for the lower combat statistics and shortened combos of Tier I - II warriors.