"Every time you mention Deus Ex, someone will reinstall it"
I found this article a few days ago and as an old Deus Ex fan I find it a very interesting read. It's about what Deus Ex could have been if Ion Storm didn't sink. The 3rd installment in the series was in pre-production @ Ion Storm using the Invisible War engine and the project was abandoned not once, but twice. In the brainstorming process there were more concurrent storylines:
1) 'Save Civilization' : the player was a Black Ops soldier operating on behalf of an incorruptible President. As an eye witness to the destruction of Area 51 in the original game, you'd use cybernetic augmentations to flush out Illuminati agents, restore democracy and set the stage for Invisible War. It was to be a fast-paced globe-trotting adventure, starting with an NSF siege on the White House and touching down in Moscow and London along the way.
2) 'Foster Family' : is a years-long story around a core cast of adopted family members that could bear the consequences of your choices and influence your career within the CIA.
"The more the player succeeds, the more he earns the trust of US officials, many of whom are close friends of his or her fiancé's," explain the notes. "Missions then become riskier and less conventional...[such as] transferring terrorist funds to a Swiss bank account or laser-sighting an American citizen for aerial assassination."
In the Foster Family pitch, family members would constantly offer their thoughts regarding the grand - but oddly undetermined - conspiracy at play.
3) 'Infiltrate The Cult' : took place after Invisible War, canonising the JC Denton ending where humanity is linked together by nanite-enabled groupthink. In this story, Paul Denton organises an offline resistance and prolongs his own life using Illuminati cryogenics.
Here is the full article, enjoy! http://www.eurogamer.net/articles/2014-11-16-ion-storms-lost-deus-ex-sequels