Originally Posted by
jaakkeli
The point about it being equally obvious that Leah is possessed by Diablo and that the Dark Wanderer was possessed by Diablo is a good example. In D2, you arrive at the rogue camp knowing that some dude they're calling the Dark Wanderer has demon trouble following him so you start trailing this Dark Wanderer. Pretty soon you'll figure out that it's Diablo but it doesn't matter, once you know it's Diablo the logical thing is to keep doing what you're doing, following his trail. The story is written so that it doesn't matter whether you realize the Dark Wanderer is Diablo, your actions will still make perfect sense.
In D3, you figure out pretty soon that Leah is possessed by Diablo but then you're forced to follow this spoon-fed plot where your character still doesn't realize it and goes along with working for the obvious traitor. Once you know that Leah is possessed by Diablo, none of the plot makes any sense anymore. Why would you go along with the plan once you realize where it's leading? The story is written so that you have to pretend that your character and Tyrael are too stupid to realize what you yourself realize since the plan makes zero sense once you realize Diablo is in Leah.