How do you know its crappy?
Because a FPS gameplay is not made to be played with touch screen controls? (especially when the game is based on stealth, and so require precision in the controls). So the same reason why 99% of the mobile games ported from a PC/Console concept don't work.
And the same reason why, at the contrary, Angry Birds is useless on a PC/Console (except maybe on the 3DS because of the touch screen functions).
And also because it's a spin-off of a novel near no one read (not even most of the Deus Ex fan) so it's pretty useless? (I don't think Deus Ex is a an enough known licence to appeal casual gamers, most actual gamers, even old ones, really discovered it with "Human Revolution" in 2010, though most of them known the name. It's a bit like "Twin Peaks", near everyone know the name, but only a really low number of thems watched it).
They would have done a lot more of money with a new Final Fantasy on IOS/Android.