I'm playing X-Com: Enemy Unknown on 360 and it plays quite nicely with a controller. I would argue that, even though it isn't an RPG, it is probably a better example of how D:OS could work with controllers than Baldur's Gate, Torchlight, Diablo, etc. That is because X-Com (like D:OS) is turn-based.
I'm not arguing whether or not Larian should spend their time with controller support or console ports (actually though, I would enjoy controller support on PC), just pointing out that tactical, squad-based, turn-based combat has been done well on a console platform.