Over the weekend game designer David Brevik published a scan of the original 1994 design proposal Condor, Inc. (which would later become Blizzard North) used to pitch Diablo to potential publishers.
Brevik made a promise to publish the document online after referencing it in his Diablo classic game postmortem at GDC last week, and it's worth perusing to get an understanding of how one of the most influential action-RPGs of the '90s was originally conceived.
Note, for example, that in the original pitch Diablo was described as a turn-based role-playing game with randomly-created dungeons at its heart, something Brevik alluded to in his aforementioned postmortem when he noted that the game's design was heavily inspired by his love for games like Nethack and Rogue.
He also described how the game came to be real-time instead of turn-based; at the gentle insistence of representatives from publisher (and eventual studio owner) Blizzard Entertainment, who were convinced that "real-time will be better."
We've taken the liberty of excerpting a page from Brevik's (brief) Diablo pitch below, and the full document can be found over on his blog.
Incidentally, if you enjoy reading Brevik's memories of making Diablo you might also like to read up on what it was like to develop the sequel in this classic Diablo II postmortem.