I think the difference here is that the Jailer and Sylvanas have yet to give a real reason why the current system is so horrible. At best it just looks like Sylvanas is pissy that she cannot go to heaven after being evil.
More importantly though is that the solution they seemingly give is to just destroy everything and kill everyone.
One of the gravest sins a writer can make is to have a resolution be at odds with the way the story is told. If a story is about a foster kid who gains friends and a loving family through a caring system you cannot then have the resolution be that the foster system is terrible.
Similarly the story in Shadowlands is that everyone goes to a fair afterlife, with at worst a few stragglers that are misjudged, mostly based around the Kyrians. You cannot then have the story end by telling us that this is not how it is supposed to work. We have yet to even see a fundamental flaw in how the afterlife works that needs rectifying outside the specific case of the Kyrians, and even then it seems more that the problem is that they don't want to give massive powers to those that intend ot use it for the wrong reasons.