I’d say that the whole thing was framed under the usual characterisation that you’d expect from Sylvanas: carrying out some shady stuff in order to secure her own people’s agenda.
Only this time, she at least tried to signal some degree of restraint.
If only because she prefaced this scheme she had with a “No, you take my army and carry on fighting the Legion, Champion. This one I’ll take care of without making the entire Horde army be a puppet for my own goals”.
Yeah, it was all shady as hell. But it was still your another day with the Sylvanas we knew.
The one that still showed signs of improvement.
Come BFA, that was all thrown out the window and replaced with the screeching “Horde is nothing” and “Souls to the Death God” impersonation.
Same.
Voljin a death would’ve still been a bitter pill to swallow, but at least we would’ve had a meaningful payoff.
With what came after, not only did he die an underwhelming death that removed the only iconic OG troll we had, but also made a fool out of him.
It was all authorial fiat.
We had stuff like Saurfang warning Sylvanas he’d challenge her as soon as she stepped a foot beyond the line.
But it was all discarded for the sake of plot and to stretch the second attempt at a civil war.
It’s not that characters were stupid to not learn from the stuff that happened under Garrosh.
Writers KNEW they should’ve reacted differently.
But they wanted to tell this story, so they temporarily gave them the attention span of a Goldfish.
And for the first round or why did the troops/leaders comply, I’d say that writers did in fact bother with plausible reasons.
At first we had factions revolting against Garrosh or downright disobeying him (Frostwolf collaboration in Silverpine, how the Forsaken were to conquer Gilneas, etc.). But these same people would end up submitting if only because his arch portrayed him increasingly deranged and dangerous towards dissidence.
Fear basically reigned any act of rebellion.