It makes sense, though -- McCann said he was inspired by Deus Ex's "transhumanist" themes, and tried to blend more human, acoustic music in with electronic tones. Vangelis gets a mention, and it of course did the Blade Runner soundtrack, which this latest iteration of Tron also draws influence from.
The first Deus Ex has surprisingly little influence on McCann's soundtrack (there's just one cue he deliberately used), but that doesn't mean we won't hear it. McCann said that audio director Steve Szczepkowski did find "a few clever ways of using DX1 cues, but not in the places, or in the ways, that you'd expect." Intriguing! Our ears will be open when the game comes out in August.