I dont understand is that hard to come up with a new villain?! they kill soul edge like 4x times already?! How about a new sword or dude comes to the scene that wants to destroy the world or something, and both soul edge, and soul caliber need to stop this thing before it destroys them.
The series' concept is about the "tale of souls and swords eternally retold" for a reason. Besides, a new villain implemented how you want is, honestly, not only a little cliche (moreso then SC already is) but also, in my opinion, wasted management. Soul Edge is the big bad, he is the recurring villain, the central plot point that keeps the series together.
Suddenly going, "Let's change it up and have a new villain," detracts from the overall concept of SoulCalibur: a fighting game series telling the story of many people from across the world all connected to the conflict between two swords.
Besides, I cannot see most of the characters willingly working together for their respective "master" without trying to kill each other at every turn.
In essence, it is not that the developers cannot come up with a new villain (Algol, anyone?) but that a new villain is always going to be connected to the Evil Sword because that is the whole concept of SoulCalibur's plot! Besides, it is not like Soul Edge is an actively evil face we always see time and time again, it shares a role of duality as plot device and antagonist (due to its unique nature) and usually ends up being a major character but not the overarching enemy (as Nightmare).
-SE/SB=Cervantes
-SC=Nightmare
-SCII=Inferno
-SCIII=Zasalamel
-SCIV=Algol
-SCV=Elysium
New villains were added three times to the series, with Zas and Algol being really interesting and dynamic characters. Elysium is a bit of a headscratcher for me because now there is an obvious conflict with SoulCalibur being just as destructive to humanity as Soul Edge. You are welcome to your opinion, but I ask you at least understand why the swords are so integral to the plot in their constant battle for supremacy.
--Forgon