I strongly doubt that they would stop after they conquered Lordaeron.
You see, their claim that Lordaeron belongs to the Forsaken because they were it's people in live.
Then they want to take the Arathi Highlands and turn Stromgarde Keep into "New Undercity"?
As protection? Offense is the best defense, when the Forsaken got a full hold of Lordaeron they will start to roll into Khaz Modan, may sound strange but the Forsaken have no claim of Stromgarde either.
Forsaken will not know peace until the enemies of Sylvanas are dead.
So, those ressurected don't have a choice after all?
So they get the choice between to serve the Forsaken or roll over and die?
If it's thats the choice then i fail to the see options.
Garrosh wants to cure the Horde of the imperfection called "Emotions" only those emotions that strengthen should remain, also Garrosh doesn't give a shit how his enemies die, as long as they die.
Vol'jin and Baine were not fine with Garrosh war from the start, but they started to really despise it after Garrosh has shown that he would stoop down to any level to win this.
Again, in the short story it is pretty clear that Sylvanas cares for the Forsaken because she knows that will be killed when the Forsaken are dead, she needs to keep the Forsaken alive to keep herself alive, she doesn't act because of love for her people.
Or why do you think Sylvanas jumped off the Frozen throne? Lich king is dead, the only purpose in her unlife now fulfilled.
She came back because she realized that being actually dead will be worse than anything that could happen to her.
So what?
It's like discussing which dictator is worse, Stalin, Mao or Hitler. All 3 are giant assholes who killed millions of people, i seriously do not care which of them is the greatest asshole.