Please don't claim that oil catch cans fix a problem which doesn't exist.
They in fact are useful. They prevent oil entering the intake tract. The oil mixes with EGR soot and forms deposits on intake manifold and intake valves.
You need to see a really clean manufold/head of an engine with oil catch can to really understand tha the problem in fact exists. I fyou eliminate oil, the buildup almost doesn't occur. The soot remains dry and gelts blown away by the boost pressure.
Regarding the VW valve covers with oil separation capabilities. They suck. Seriously. I've seen many engines having positive crank case pressure because the breather is simply failed. In addition to that, the oil separation isn't very effective on it.
One recent thread, as an example:
http://forums.tdiclub.com/showthread.php?t=478494
My city-driven CR-TDI manifold looks similar too.