From Diablo Wiki
Pentagrams, crosses, and other traditional Diablo-style holy symbols are not present in Diablo III, and have also been retconned out of World of Warcraft in recent expansions. This is an intentional design choice by the developers; in addition to helping them avoid potential controversy, they feel that removing symbols from existing real world religions will help them make their games more original and self-contained.
This change has created a lot of controversy, with fans objecting to the change on aesthetic, symbolic, and "gutless corporate weasel" grounds.
Bashiok: A lot of what we do now and have been doing for the past... 8 or so years, around the Warcraft III and initial World of Warcraft development era, is putting a lot of effort into crafting unique worlds. Meaning that we put more effort into every aspect of the game world itself. Who is this secret organization? What is their history? What’s their look? Do they have a specific accent? Do they have a symbol or mark that can identify them?
In the previous games I think there was a sense of “Oh it’s a demon, Diablo, devil, Satan, satanism… pentagram!” and while certainly there are those influences, what we’re creating now and have been creating for quite some time is evolving the game world and making something more complete. A complete world where every aspect is fully realized, maybe even if it doesn’t show up in the game.I think that same sort of world-crafting can be seen between Warcraft II and Warcraft III. A big shift in focus to fleshing out a unique fantasy world and story.
- FLUX: [Diablo 1] had a lot of Christian references… a lot of crosses and pentagrams and sort of parallels to Christian religion. You know, real existing faiths in your mythology of your Diablo games.
- MAX SCHAEFER: Yes.
- FLUX: Obviously, you guys planned that. It wasn’t just like, “We can’t think of something better or something different so we’re just going to slap in some crosses.”
- MAX SCHAEFER: No. And it wasn’t necessarily because it’s Christianity as such. It’s just that it evokes images and ideas that people are familiar with. It’s not just a cross, it was a cathedral. It was a town that had the architecture style of what you would find in medieval Europe. There were lots of things beyond that imagery that was drawing upon real world parallels. It was just because that’s what evoked the ideas that we wanted to evoke.
- FLUX: As we’ve seen recently ...Blizzard has removed all of the crosses and pentagrams from Diablo and also from World of Warcraft apparently. Some of the stuff upon release has since been sort of... I would say sanitized. Their explanation is that they’re creating their own original individual world and their own mythology. What do you think about that? I believe you said last time that you wouldn’t have done that if you were still on the project.
- MAX SCHAEFER: We definitely would have not done that, because it doesn’t... the idea that it’s just because you want to have a new world that you’re creating something in just doesn’t wash. They picked out those two things because they’re controversial. We wouldn’t have done it. I don’t begrudge them their decisions. Again, they gotta pursue what they think is right with the game. But, we would not have done that.