I'm interested with a few flags...
First of all I'm an aviation geek so the plane crash has to make a certain amount of sense. Since it's Sydney we're leaving from, it's probably the big new Airbus A380, we could easily have the engine blow up *gniffle*... that leaves us though with the problem at how such a big airplane crashes into the ocean and only a handful of survivors.
It would make more sense to leave from Sydney in a small propellor plane to fly to one of the islands of New Caledonia or Vanuatu or something like that, More changes of survival. Problem with that is the location is not very remote.
Of course Im willing to drop my OCD a bit and find a way to make it work without being overly pedantic
The other flag is the number of characters and the characters themselves. So I'll wait for that a bit.
What if the plane split in two, mid flight. One half crashing on the beach, the other deep into the island. More then likely, the ass end being deep into the island. So that, when more people come, they have been surviving in the jungle, as we were surviving at the start, on the beach. If the nose, is where we came from, then it makes more sense that so little survived.
Reason A) Nose is source of impact.
Reason B) Proppeler's, engine explosions, and gas fire at the heat and destructive power of napalm, is not very friendly to the masses. Air planes, crash hard. Pretty hard. It may be the safest way to travel, but when it does crash, it leaves little alive in it's wake. In my mind, it makes sens if we suffered wounds. I mean, a crash of the magnitude needed for little to survive, leaves little room to come out clean as a whistle. Cut's, burns, broken bones. Hell, as an interested party, I throw my hand in the air for playing a character whom is temporarily crippled. Maybe through a year or so of in game time. Slowly goes through some debilitation, with the help of his island friends. Not definite, but a possibility.
I must also invoke a personal preference, and opinion out there. Ban on overly survivalist characters. It sucks when 10 different people walk around being the heroic, bad ass I want to be leader so I make myself able to handle anything, macho man types. Ruins the fun for people who want to go throughout the rp naturally, and develop bonds, survive, and naturally form a leader, and group. Maybe even split each other into separate groups at some point. Like in Lost. So, to strengthen my plea, how about we are all allowed a set number of life skills we can pick up. So that each person can be made to be use full in specific fields.