So, for all that have not been keeping score -
Blues have stated that they don't want the Felguard to be the level 10 Demo ability.
In the current build, it is. It is also the only reasonable ability short of the Demon bolt that we have yet to see.
Blues have also stated that they would like to offer the option to re-skin our demons, and would like to offer a new demon if they can find uses for all the current demons.
So, I have a solution to all this.
At level 10, a demonology warlock gains the ability to "trade in" any demon he knows how to summon for another one that performs the same role. This can be done in any number of ways including a tame mechanic similar to hunters, a drain soul mechanic to gain a "demon shard" that would be used to set the new demon, or little mini quests to capture your demon of choice. The method really doesn't matter all that much.
Demon names would still be random by race and unchangeable, just so that golden cow remains as is.
Trading in your demon would give you a damage boost appropriate to the demonology tree as well as one interchangeable utility ability per skin. For instance
Base - Imp - Firebolt, Burning Ember, Blood Pact, Phase Shift
Upgrade - Eredar - Firebolt, Burning Ember, Blood Pact, Blink (targeted teleport)
Upgrade - Mo'arg - Firebolt, Burning Ember, Blood Pact, Shock Grenade (short stun)
Base - Voidwalker - Torment, Sacrifice, Consume Shadows, Suffering
Upgrade - Felguard - Torment, Charge, Consume Shadows, Suffering
Upgrade - Unbound Voidwalker - Torment, Vortex (a grounding totem like effect), Consume Shadows, Suffering
... keeping in mind that Torment will be dealing damage to multiple targets according to the sneak peeks a few months ago, I figuered it would be a good stand in for cleave. Maybe a medium or minor glyph can be used to add damage in exchange for the extra threat.
This solves the logic problem of getting the felguard before the voidwalker. This way, a new warlock would go catch himself a Felguard after he learns how to summon a tanky demon. It also allows some warlocks to re-skin their demons with a minimum of developer time and energy, as well as providing the demonology tree a bit more flexibility on which demon they use to fit with their "master of demons" niche.
So, this is my grand scheme. Please let me know what you think of it.
P.S. I figured this would be best placed in the warlock forums, as the cataclysm forums don't have class sections.