Because Deux Ex was produced for the glorious, now near extinction, PC gaming master race. New Deux Ex is being produced for the console tards. That's the short answer.
The original Dues Ex was produced by Warren Spector, one of the greatest game directors of all time. When it comes to blending FPS gameplay with RPG elements there is nobody better in the industry. There is a reason why Deus Ex and System Shock still haven't been topped since their production.
The last time an attempt was made to update one of Spector's creations it produced the massive steaming pile of shit known as Bio Shock - otherwise known as Baby's first FPSRPG. Basically they took System Shock 2, cut out all of the depth and strategy, dumbed the difficulty down to ****** levels and then spent the rest of the afternoon rendering the Big Daddy sprites.
The end result was a completely generic, brown FPS with a few meaningless RPG elements tacked on for good measure and a bland an uninteresting moral choice system. The story was completely mediocre, disguised only by the bottomless depths of shit served up by most other games in a genre (Read: Gears of War and Halo).
This is exactly what I expect from Deus Ex. After the shit Kane and Lynch went through there is absolutely no way the game is going to limit the ability of the protagonist's gun play. As such a franchise that was originally
all about stealth and finding alternative ways of doing things is now going to present the player with the ability to run and gun through every situation. Released footage pretty much confirms that I'm right about this.
I'm sure the developers will still produce multiple routs to every objective, but when every player can simply shoot their way through every circumstance there is little incentive to take any of them. There also won't be anything like the depth of game world presented in the original. That's simply a product of the time period, with so much rendering now required to make a game graphically acceptable there is simply no possibility of building a world comparable to that of the original Dues Ex. It's the same reason Enix has been refusing to remake Final Fantasy 7 despite the whole game world clamoring for it for for years. This console generation has hurt game design like never before, and that is why you see so few PS3/360 on my list of game submissions.
Story will be shit. I have nothing to back this claim up, but I'll still be proven right. This game has been hyped for an age and is being marketed directly to a main stream gaming audience. As such you can guarantee not to run in to any challenging thoughts or ideas throughout the entire game play experience. If the narrative can manage to match that of the last worthwhile Call of Duty game then I'll consider it a bullet dodged. Low expectations.
At the end of the day, if you've never played Deus Ex then there's a good chance you'll like this. If you enjoy FPS gameplay and thought Bioshock was a really clever game then you'll probably get similar satisfaction out of this. However; if you've actually played and appreciated the original Deux Ex then you'll recognize Human Revolution for what it is. A repackaged, dumbed down version of an all time classic, inferior to its predecessor is almost every way.
Nothing would make me happier than being proved wrong... but I won't be.