(TL;DR version at the bottom)

You have stats that are affected by weather- comfort level, hunger, thirst, can become sick, etc.  It is all skill based--100's of skills you have a recipe list on your ui with about 4 simple recipies of very low quality. You learn new recipies by gathering new items and by reaching a certain skill level in a respective crafting skill.

. You find yourself shipwrecked on an island.  (Think Risen)  You can pick up most of what you see off the ground. (Think Xsyon or more except everything you can pick up has to be visualized graphically) You find a box that has also washed ashore probably from your shipwreck. It contains an axe and some string. Thats all you can manage to scavenge from your shipwreck.

Everything can be picked up, logs, sticks, trees can be cut down. Think of everything that a sandbox mmo would have and expound upon that.  You notice crabs they can kill- smaller type animals at the start at the beach. The deadlier animals are in the jungle. Your run-speed skill is almost zero (because its hard to run on the beach and in the jungle until your feet aclimate to it) .

You have a recipe list separated by categories. One of these is shelter category with a recipe for "Poor Shelter". You see you need large leaves and long wood poles. Cut down trees and shape the wood and cut leaves off the appropriate tree and create a shelter for that incoming storm. You can sleep under the shelter. When you wake up your comfort level is a little higher but your hunger and thirst bar is low. 

You take the string and tie it to a stick you have scavenged to make a fishing pole. You also find a hooked barb that you can use for a hook. You go fishing. Your fishing skill goes up but you fail to catch anything.

((Anyway... you get the point))

Eventually you can make bigger and better shelters, then huts, as you move closer inland into the island. You can also start to kill the bigger game on the island. Finally you notice you may not be the only person(s) on the island. (Think of the LOST series, and the story begins.)

(Im not going to make up a whole story about the natives and whether you befriend them or become their enemy etc)

---The whole point is making a crafting-heavy realistic survival type single player type game (without guns! you Farcry-fans). The recipies in the game seem almost endless. Certain items may be able to be used for different things(a course rock could serve as a hammer, projectile weapon, or as a sanding tool,  A boar hide can be used as a tarp, clothing material, container.)

By the end of the story you are able to craft a huge boat you are able to sail away on... if you want to.

TL:DR version

Combine Sandbox mmo crafting with survival type game(hunger bar, comfort bar-weather), with sandbox skill based gameplay on an island you were shipwrecked on. No guns, No technology.Build and decorate bigger shelters, sleep. Find your food.  With a story that gets larger as you move inland of the island where you will need higher skills to beat.

I have actually suggested a Lord of the Flies MMO before, but there would be nothing quite as cutthroat on the market. Same thing pretty much, but can lose direction because of player intervention. I do think a single-player type is much more fitting.

It could have a very narrative tone as well, as going to sleep each night could bring up a cinematic of places around the island with points of interest to check out on that day, and a splash screen saying "day X". The weather seen from those angles could be indicative of whats to come later, storms and heat spells, etc. The main character would have to talk to himself an give kind of a primer as to what needs to be done, or with simple reactions in crafting and survival events. It would be an extremely boring game if the main character was as silent as we would be by our lonesome, but it leads to interesting and self-aware angles where he could be losing it, or find his own "Wilson".

The one thing to consider is not making it a static journey. IMO, there should be some variance on daily events and weather (randomized, even) and the length of time stranded there should vary upon your actions. Say a plane goes over every 8 days, and it's one of many ways to find rescue, but you could miss your chance to start or keep a signal fire going, or perhaps have a piece of mirror and fail to get a reflection beaded to it's location because of the sun's angle. Even then, there should be a sign that a rescue is coming, perhaps a drop that floats in with a few essentials, and then the game goes into 'overtime'. When rescue is imminent, the game should work harder in trying to kill you. Maybe a wicked storm, in another game a giant boar hunting you, in another game locusts (or something). It's the kind of game you play once then never touch again, unless there is reason to, and as long as one playthrough is moderately short enough to bother with.

Oh, and perhaps a note from the Dead Rising school, where stats/skills rollover to the next game, allowing you to upgrade early.

Sounds like a good idea, but you have got  to be careful about skill advancement. The moment you have people making dozens of useless (at least at the time) items in order to get to what they actually need/want, you lose that sense of working for survival and it simply becomes work.

If you want ideas to flesh things out, there are two very good literary sources I know of you can use, both of which I'd recommend reading anyways if you enjoy fiction. Swiss Family Robinson by Johann Wyss, and Robinson Crusoe by Daniel Defoe. (don't know if the shared name was intentional.)

The second book is a little closer to the scenario you're suggesting, involving a single stranded individual with few supplies rather than an entire family that recovered quite a bit from the wreck, but both involve the protagonists using the resources of their environment to create the tools they need to survive.

I'd say that deciding what kind of resources are available is just as critical. For example:

-Softwood trees are easy to cut, burn easily but quickly, and also tend to make for only adequate building material. Hardwoods give off a lot of heat for a longer period of time, and last very well for both tools and structure, but are difficult to cut, shape, and set on fire. How you treat the wood also makes a difference. Green (freshly cut) wood is flexible and easy to work with, but warps over time and can be brittle if abused. Wood that is properly seasoned before using it to craft with tends to last far better, but seasoning takes both time and a dry place to properly store the wood.

-Different kinds of stone can vary from extremely useful to almost useless. Flint and obsidian for example were used by our ancestors for very good reason. It takes a lot of skill to properly shape them, but they make for incredibly sharp edged tools, rivaling even their modern steel equivalents (in terms of cutting edge, not durability). An island with large sedimentary deposits  such as chalk is likely to have flint. A volcanic island is likely to have obsidian.

-Different plants can provide all kinds of resources, from food, to medicine/poison, to naturally derived rubber (believe it or not, there's a tree whose sap can be used to make a latex like product)

I would suggest one other item being recovered, a simple journal. Journal entries can flesh out the storyline, providing information from the character's perspective. It can also be used to give hints for crafting ideas and/or document information about the possible resources your character has already encountered

Sounds like you want to play a more in depth version of Minecraft. There are island maps generated in that game. 

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