I just wanted to suggest that you have two ways to win. The first way to win is just like the rest of the BR games "Be the last person standing". The second way would be to extract of course, but in a different way.
For the extraction part you should have a flare gun on the map that doesn't spawn till a bit latter after the map shrinks a bit. Once the map shrinks enough you will see a Orange flare gun box some place in the map. You fire the flare gun off and the extraction comes to that location.
At this point everyone on the map is now aware of an extraction going on and will head to that spot. However you have the ability to shoot down the helicopter leaving the game to be won by the last man standing. It add's a bit more flair to the game.
Side addition. I would also like to see key hidden across the map that open up caches laid across the map. In those caches is at least 1 great weapon or piece of gear. This will on add another element to the game that will keep things fresh and interesting.