Thanks for sharing this idea! To clarify, would you like the date the event will close to default? Right now, when you copy the event you are brought to the Event Basics where you can check this option. If you don't choose anything in this section there will not be any limits set for closing the event.
I use both! My events are planned around the number of people registered by a certain date. I have a maximum so If it fills up in 10 minutes, I need it closed. I time to prepare materials so I also need it to close registration at the cutoff date. If they can still register on the event date, they will not be included on the guest list.