It's a bit old, but if anyone was curious as to the games that never were, check this out:
It's an interesting read. Like for example Kai Leng was actually supposed to be a credible threat, instead of a dude who hid behind his gunship. Also, all the female romance options in ME2 were originally supposed to be for FemShep as well. And (not very) suprisingly, both Zaeed and Javik were both cut from their introductory games to be DLC.