That seems very doubtful to me. I can't see a MM Hunter, for example, dropping the class because Blizzard added a 4th spec that allowed him to heal but left MM alone.
Why would they add it as a spec instead of a standalone class? Because Warlocks already are Demon Hunters. Right now. This minute. You can log into the game and play a Demon Hunter. You just have to accept they are called Warlocks. It lacks viability and it doesn't have dual wield but if you wanted to go around as a demon hunter...that's already in the game. Same look, same theme, same moves. Players got excited during the Beta about getting to play Demon Hunters and tanking and were disappointed when the viability of that got nerfed. But actually BEING a Demon Hunter? Warlocks do that right now. What they lack is the ability to dual wield and viability in the role.I just don't see the point in adding Demon Hunter as a spec for Warlocks when it's such a popular class idea for two distinct roles; it would be massively underwhelming and completely defeat the object of the attempt to give players what they actually want.
If Warlocks just lack Dual Wield...is it realistic to expect Blizzard to add another class that is effectively the same in many ways? And if you redesign the class so its different...is it realistic to expect Blizzard to call it a Demon Hunter and so weigh it down with the baggage and in game lore of the existing version?
So, to answer your point....it IS viable to add a spec for Warlocks that reflects a viable melee role for what the Warlocks already have for a tanking role that it already fills in game. A viable melee DPS spec would only need to be developed if the DHs were added as a standalone class.
So sure...Blizzard could do that But why bother when all it has to do it tune the existing Warlock into viability instead of redeveloping a new style of tanking. And even were Blizzard to develop it, that wouldn't change the fact that Warlocks are Demon Hunters right now. You'd have to actively remove abilities and options from the class to change that. Which again, isn't impossible but ti does seem unlikely
They could indeed create new lore. Why would they need to? They also do NOT need to destroy the little Demon Hunter lore that exists. Which is minimal. They use Rituals, and they are shunned. Sounds very much like warlocks. They wouldn't even need to destroy the non-canon RPG info since little, if any, of it actually contradicts the supposition that DHs can be seen an offshoot of Warlocks.Blizzard would be foolish to try to combine the two, considering they could create new lore to explain the tanking form instead of destroying existing Demon Hunter lore.