Yes this topic was covered before, but I have a different idea.
Instead of sections of the sail that remove or zipped holes you can open up, what if the sail itself was made of some sort of material that would open up thousand of tiny holes after a certain wind velocity was reached?
The holes could be nearly invisible or up to several mm.
You could have sails based on a certain max windspeed, the smaller sails for the higher windspeed would open up the holes at a higher wind velocity while a larger sail would open up the holes at say 20 knots.
This way one would not find it necessary to come back in and rerig to a smaller sail as the wind picks up.
With the holes evenly all over the sail the feel or COE should not change.
For all I know material like this may already exist.
Then we would see the skill of "harden the f*** up and just hold on" slowly die out.
I don't think it would work the way you want it to.
Bleeding the air through hundreds of small holes would just make the sail really draggy. that is, lots of drag in the forward direction.
Some old aircraft used to use this system on a centre flap. Rather than just a solid surface, it was a cheeseboard type thing. I think the Moth Minor had one from recollection. They worked good as a means of increasing drag and slowing the plane down on final approach.
Not something you would want on a windsurfer sail unless you wanted a brake coming into the beach. 
Trying to think outside the box here.
The holes would only open up from the force of the wind over a certain velocity.
That is the hole would be variable, opening and closing in response to the wind over a set velocity.
Perhaps stretching open.
Under a certain wind speed it would be just like any other sail.
Keeps us from having to rig down, but wouldn't help having to rig up unless you over rigged to start.
Thinking about it some more, it would only help in really gusty conditions because you wouldn't want to be sailing along with a holy sail.
Or would you?
You are thinking of the sail like a simple sheet of fabric in the wind - and the little holes like they have in advertising banners to stop them tearing. A mediaeval ship with big square sail going downwind, yes your idea would work.
Trouble is, our sail isn't - it is a wing shaped foil with a relatively laminar airflow due to apparent wind.
It would not work as good as twist (otherwise I reckon we'd already have sails full of holes instead of twist 
)
Once you have enough power that you need you should reduce sail size (provided you are fully powered up) so it reduces the drag coefficient. the biggest problem we have is drag.
The other problem with having a sail with holes that open up is that one sailor is very different to another and the righting moment changes a fair bit. This will result in how much pressure the sail should open up to. It would have to be custom designed to suit. Other way is to twist the sail off earlier or later which is easier than changing sails....still the drag factor exists.
I don't get it. Once the board and rider are at say 20 kts, the sail will be light so there will be only incremental power in there enough to keep you on the plane. as the wind increases so would the speed of the rider, but the force in the sail would only cause the holes to open in the gusts. You would find it challenging to get planning on this as you would loose power through the holes when you pump the sail.
Maybe I am thinking about it all wrong. Can you draw a picture?
