He**gate: London was showed off to be so much like Diablo, because some people that helped with the Diablo series left Blizzard (Blizzard North I believe) and went to work with the company Flagship. I personally don't think that they were going for an exact copy of Diablo or anything, but just wanted the dark feeling and some other things from the game. But I agree, there was tons of hype regarding how much it was supposed to be like Diablo and all. A good amount of people were disappointed.
In other news about Flagship, I guess recently there is a rumor going around that they cut a bunch of their workers and that the company is starting to go down. In some websites, people say that it's true and in some others, they say that it's a false report from some guy on his blog. I think that it's false myself, but who knows. Their website looks to be fully functional and says nothing about it, and they have job openings available.