Warzone is supposed to be a fictional simulation. Warden as the boss everytime is getting old.
Guilty Spark’s model is already in the game (as forge monitor), so 343 wouldn’t even have to add any new models/animations. Guilty Spark making an appearance in a simulation totally makes sense to me. Why not make him a boss and behave similar as to he did in Halo 3?
VIDEO LINK
If he fired his beam a bit faster and it was lethal (like warden’s attacks), he could be a fun legendary boss. Him having a small hitbox and moving fast would be a fun challenge in accuracy, too.