Using the name and legacy of a good game to market a different game that is basically nothing like its predecessors in spirit. Diablo 3 is Jar Jar Binks to the original Star Wars trilogy.
They did the same to SC2. It was like the summer interns that wrote the plot had never actually played SC1.
(yes, I'm salty that I played through a huge chunk of a single-player campaign chasing "prophecies" in what had previously been a sci-fi setting, even if it was 50s psionics sci-fi).