Warcraft III is totally different than Warcraft II and it uses a new engine that Blizzard has never used before. Working on the Warcraft III engine was a great experience because we were making so many technological leaps all at once. It was also the first game we wrote that was designed from the ground up to be completely open and customizable by users. That goal permeated everything we did and caused us to write a very clean, general-purpose, extensible game engine. Warcraft III also had a completely new network model that was probably the most advanced network model of any game in the industry.
Any programmer loves a chance to build a new project from the ground up.
Having solved a problem once before, the code you write to solve it the next time around is always cleaner, better, faster, and more powerful. That s one of the reasons I m really enjoying developing a completely new engine here at Arena.net. I think that when you re able to see what we re working on, you ll be blown away by it. Creating completely online games is an innovative step, and sounds quite exciting and challenging. I think that the biggest challenge is just the sheer amount of work we have ahead of us.