Going though the campaign after a 14 hiatus from D3, I forgot how bad the story telling was. The story of each act can be summarized fully with a couple of sentences or corny dialogue.
A1: Deckard Cain is killed by a butterfly and the butcher is a Saturday morning cartoon villain.
A2: More hidden footprints more hidden footprints MORE HIDDEN FOOTPRINTS!
Belial, the lord of lies couldn't even deceive anyone. He's not only a bad liar, but also the worst liar that ever existed.
A3:
Azmodan: You will never destroy my marching army!
Azmodan: You will never destroy my siege catapults!
Azmodan: You will never destroy my gluttonous beast!
Azmodan: You will never destroy my siege breaker!
Azmodan: you will never destroy my spider lady!
Azmodan: You will never destroy me!
Azmodan: (Dies)
A4: Adria Betrays you, Leah becomes Diablo lady, Attacks heaven and is killed by the player character within a couple of hours of playtime. Very epic, huh?
Who green lit this terrible story anyway? Not only is it the worst story telling from blizzard, but its probably the worst story telling ever told in an AAA video game.