Here is what you would be accomplishing. It would be similar to the old draft tube design of the 20's through the 50's where the venturi effect would create suction when at speed. But they used on tube, and a media breather on the valve cover to allow in the fresh air side for evacuation. What they did know at that time (todays oil analysis shows the contaminates...back then they only had theory) was that due to reversion, those tubes also pulled in dirt/dust/water/sand directly into the crankcase and resulted in motors lasting only 30-50k miles at best.
If you do one hose from each valve cover, at speed one will have more suction from the venturi effect and overpower the other causing it to act like a vacuum cleaner sucing the road dirt and debris directly into your crankcase. (see this more and more done by some tuners w/out a clue to the functions of the PCV system) Your motor won't last long.
Then, you are defeating the crankcase evacuation that is so critical to engine life. You are allowing pressure to release, but very little evacuation takes place so the majority of the damaging compounds present in the blow-by gasses are left in the crankcase and every cool down condense and accumulate into a mix of damaging compounds.
Abrasive carbon particles (the ones too small to be trapped by the oil filter)
Sulfuric acid (attacks the metal parts and bearing and journal surfaces).
The PCV system provides several very critical functions to give todays engines life for several hundred thousand miles, and pressure relief is only one of them. If you are not constantly evacuating (not venting, that does not remove the damaging compounds) these while they are still in a suspended or gaseous state, then they sty in the crankcase.
Look at this rocker arm end from an engine with just breathers on and the PCV system deleted. In just a few months rust pitting is already attacking the top of the rollers needle bearing bucket weakening it:
Imagine after a few years like that.
Same with a can with a breather on it like some turbo vendors do, or one of the V6 superchargers that just fill with water, it defeats all evacuation.
For an engine to live properly and prevent the damage and premature wear these combustion by-products cause, it is critical to always be evacuating the crankcase. The oil is an unintended by-product of the excellent designed OEM system. Going back to the ways of the stone age (well nearly) is not the answer, neither is using a can that allows just as much oil to pull through as it catches the solution. There is a need for a properly functioning catchcan on every gasoline car and light truck made today, and only a small handfull are worth installing.