I'm OK with her vocal quality. Her delivery on the other hand ...
Perlman isn't half bad. But I'm not sure he suited to the role. Sargaras needs to sound imposing, indomitable and merciless.
They changed her VA in patch 3.2. From the clip you shown me, while I agree she is better than the current VA, the last few lines during the escape still don't feel right.
This is why I call into question Blizzard's script and directing. They need writers and directors that can probably setup and execute dramatic moments. WoW's dialogue and cutscenes are IMHO a bad joke - a B movie quality joke.