How do you think the character creation is going to be done?
What I'd like to see is you are given an option of certain starting factions. Such as a Vault, a raider/tribal camp, Brotherhood outpost, NCR camp. Then a small intro is played explaining the situation.
For example; you choose to start in a vault. A little video plays explaining that the doors to Vault 13 have just opened to the wasteland. The vault-dwellers have started to colonise the outside of the Vault.
Then there is the character creation screen in some creative way. Some customisations good to include would be; height, weight, muscularture, hair(More hairstyles than Fallout 3), facial structure.
So you've done all that, you get up and leave the Vault. When you get out you see the small settlement which has been created. Here you will find your first quests and the like.
But even though you chose to start as a Vault-dweller, that doesn't mean that you have to stay loyal to them. You would be given a slight reputation bonus with that faction, but could align yourself with the Brotherhood or NCR instead if you wished.