So just what was Belial's plan there?

[Lissa]

Diablo 4? I think you mean World of Sanctuary. :op

Well, the Blizzard North Diablo 3 was going to be that...

Aye, which is why I still wonder when the D3 we have now actually started development. People spout the "They've been developing this game for 12 years!" but they haven't because I doubt any of the MMO code base came over. Sure they have been developing some game for 12 years, but not this game. They may have taken some of the lore over, which might explain why the books and such are actually pretty good, those may have had 12 years. Based on the tech the graphics engine uses it's probably 6 years at most for it's dev. But I'm guessing the game we have only really got 3 years of dev and they threw away the other 9.

Now I'll wait to be made a fool by someone who actually followed things more closely quoting some dev. That's OK I've been wrong before I'll be wrong again, but I'll also have my answer.

I wouldn't be surprised if they used the D2 engine heavily. Some of the things that make me think this is the various stairs/ramps in the game. I've been melee'd while standing at one end of a stairs/ramp and the mob has been at the other end. I've also seen things like vault ignore the travel distance up/down the stairs/ramp (ie, you still go the same distance on the screen even though you shouldn't if travelling up or down a stairs/ramp). It seems like only the spell effects are truly 3D (like they were in D2) as distance is not obeying 3D when dealing with stairs/ramps (this was highly prevalent in the Arcane Sanctuary in Act 2 of D2).