I too am a little confused around the catch cans. I understand what they are for, but like you, would rather completely mitigate any chance of oil entering the intake. I'd rather block the PCV (or have it enter a catch can like you suggest so as to vent air) and not have the PCV re enter the intake. If airflow is absolutely needed due to a sensor or something, then a filter (or hose from the intake after the filter) might be a better option.