So here are steps that worked for me:
- I did the scenario with disabled addons and Garrosh still get stuck
- teleported to garrison and closed wow ( I did NOT abandon the quest)
- scan and repair
- returned to the gate and started scenario from beginning
From the first step I saw that friendly NPCs and Durotan are more active than before. In final step I just let Garrosh talk all his lines and then slowly started to melee him, he stunned me and Thrall came, blabla, cinematic, complete.
Sorry for my english and I hope this helps