Thing is, the Cybermen in 'Doomsday' acted more like cannon-fodder, or soldiers, rather than Cyber-men - if that makes sense.
They're meant to be race of people more than a race of soldiers, but obviously, being uniform and acting like walking laptops, they can be whatever they want to be when the situation calls for it. Not counting the Cyberking, I much preferred their characterization in 'The Next Doctor' which had them being cunning, deceptive and manipulative. There's nothing in the new series cannon about the Cybermen which says they can't be absolute geniuses. The only thing that separates them from the Daleks is that they're not fuelled by emotion.
They should find things like non-cyber humans and Daleks as errors in the system and eradicate them in anyway possible - an alternative to the Nazi-like racism that the Daleks possess.
Although it would be interesting if a Cyberleader had his emotional-inhibitor damaged...