This is absurd. There are games that are "too complex for consoles" or "unsuitable for console audiences", but Deus Ex is not one of them. I can't fathom why Eidos would limit themselves to 3% of the market share* for something that is technically a shooter with a bit more involved upgrades and a conversation here and there. If Mass Effect can run on consoles, so can Deus Ex 3 - unless they've changed radically what Deus Ex means.
Sure, but that suggests that all they want to do is Mass Effect, or that ME is the epitome of the shooter-cum-rpg subgenre. It's easy to think of games that are too complex for consoles; make it more tactical, more strategy-based (think SWAT), make it for an older audience. In other words, take the Brad Wardell route. Making it an FPS makes that a more difficult fit, of course, but I could still see it being doable.
To go back to ME, ME is mostly an extension of the model they'd been building up since KOTOR, which was a dumbed-down NWN played from an over-the-shoulder perspective. Take a step back, go more complex, to something like Dragon Age and you get a game that is getting a LOT of hate on console, in great part because of the interface. Given the interface hate, I don't know if saying that Dragon Age is too complex for console would be a great stretch.