It looks like you're new here. If you want to get involved, click one of these buttons!
The writer for the diablo books has already written the 3rd installment. He even made a comment about it in a news post (if only I could find it) that he couldnt invision it not being put into another diablo game. He even talked about a supposive movie coming out dealing with what he had written. Also note some other things that look rather odd. One being that Steig Hedlund was the lead designer of Diablo 1 and 2 and until last month was employed at Perpetual Entertainment. Hmm wonder were he is now.
Yes some of the blizzard north team is working on Hellgate London but not all (and by the quality of the game, not the best ones neither.) Some of them split over to Arena.net and Guildwars. As for Diablo 3 making a comeback, most likely. Why wouldnt it? You can go ask any blizzard employee if they think blizzard would gain from another diablo game and everyone will say YES without even thinking about it. Alot of rumors tend to say that they already have a small staff writing the next diablo game. With blizzard being so secretive I dont doubt it. Also not there was a video published quite sometime ago right after the expansion came out for Diablo 2 showing off what would seem like a 3d version of Diablo 3.
Everyone thought it was World of Warcraft, but it turns out it was not. Now the video has simply vanished. If blizzard does come out with another diablo, it will be around the same time they come out with the movie which has pretty much been announced. So if your waitng on diablo 3, you will prolly hear something about it when you start seeing them talk about the movie, probably at the next blizzcon.