Oil in the breather in a situation like this is completely normal. There's a great deal of oil vapor inside a running engine as you might imagine. Hot oil (210-270F) is being slung about quite, uh, vigorously. The stock system has a baffle below the intake, as well as an oil trap/screen to help minimize the amount of oil that gets drawn into the system through the pcv valve.
You've got a few options. You could rig up a pcv valve by punching a hole in the valve cover and inserting the proper size grommet/pcv valve and connecting to a vacuum source. If you do that, reconnect the hose from the valve cover nipple to the throttle body -- it let's metered air INTO the engine when vacuum is pulling on the crankcase through the pcv.
Alternatively, leave it plugged, and add another breather to the other cover. This will halve the breathing that's going on through your current breather and help minimize oiling through the breathers. Or - you could put fittings in each cover and run hoses (at least 5/8") to a remote mounted catch can that has a breather on it. Mount the can below valve cover level so any oil that falls out in the hoses can gravity drain to the can. This will move your oiling mess to the top of the catch can instead of having it on top of the engine/valve covers.
If you have to pass emissions and the visual is stringent, the open breathers will be a problem. The pcv system is really part of the emissions control system of the engine.
