I understand you like the idea, but I can't see it happening.
Blizzard clearly liked the demon hunter too, and they broke it down and added it's essence to Warlocks. In some ways they are the same fundamental class, except the Demon Hunter is melee and the Warlock is a ranged caster.
In fact if you asked me to sum up a demon hunter without using the phrase demon hunter I would say a melee warlock.