Fat +1
This is NOT an all the time enemy. This is an enemy that will enhance the roleplay of the server by having unique interactions and custom "Lore" as their notoriety increases. And lets be real, if the Clone wars were to have a filler season 8, the writers might not hesitate to create another Dark Force User that fought alongside the CIS. They would just write it in a way that makes them fit into the story somehow. (If they felt the need for a new character)
Example:
Lets say there is a Dark Force User created by a player on the server called "Plendoo" this dark force user then uses the handful of droids that Dooku allowed him to use to mount an assault on the Anaxes base, in the process Plendoo comes across the Admiral as he raids BCC. Plendoo goes up to him and grabs his shirt and holds his saber up to his gut, asking why he should let the admiral live, but before the admiral could answer, the clones storm BCC, destroying the droids in the room, Plendoo drops Yularen and begins to fight his way out, backed into a corner he uses the force to cloak, and makes it out alive, only to face the wrath of dooku for his shortcomings. So he vows vengence on Yularen.
Thats the way I imagine it, recurring custom Dark Force Users.
I am sure with their implementation there will of course be a large list of rules for them to follow.
Also whats the difference between a GM bringing in a custom sith lord and the CIS using more lore friendly dark force users. (Note: Corrupted Jedi can also be considered dark force users, that can lead to story)