system
Given the following post, respond as if you're commenting on Reddit:
human
[Warcraft] If the scourge are an even bigger threat without a lich king. Then what was the point in killing him?
gpt
The scourge would be like a raging wildfire without a lich king guiding them, but with them they are strategically more powerful when directed well.

While the forces of good and not-so-evil would be hard pressed on more fronts across the world if the scourge ran wild, they would still manage to hold the threat back, albeit at a constantly stressful pace. The Lich King is considered a more deadly threat on the whole due to him/her/it being able to direct the forces against strategic points in the opposing forces' defenses, dealing quicker, more crippling blows that are harder to come back from than widespread, lesser waves of attacks.

While it is doubtful that Bolivar or even Tirion can subdue the Lich King's presence and influence indefinitely, they were and are both definitely better alternatives to Arthas controlling the scourge. While the former's restraint may not last forever, they are less potential threats than Arthas himself due to the latter's inherent great prowess and driving cause. As well, with the frozen throne secured, keeping the Lich King in check is made much easier (relatively speaking).