Just the fact that the lords of hell were actually talking to the hero makes it very weird&#x2F;stupid to me. 
In D2 Mephisto throws one single one-liner at the hero and other demons just laugh&#x2F;scream and thats it.
The story in the cinematics is narrated by Marius not any of the prime evils.<p>(I think Baal actually talks the most due to his conversation with Marius in one of the cinematics).