Interesting thoughts.  I've made plenty first aid kits that would fit within a small tin, for day trips and overnight hikes, but not a survival type kit.  Limited to an altoid-sized tin, I'd take:

flat pealess high decibel whistle
flat skeleton knife, as chunky and as long of a blade as possible
firesteel
3 cotton balls & vaseline in small plastic bag
15' - 20' of thin (400lb tensile) paracord
possibly a scaled down map of the area, but I'm thinking it wouldn't be legible.  Always know where you are  ;)

I think that would just about fill up the tin.  Sure, there are plenty of things that could go in it, but for our style of traveling in the BW and Quet.  it isn't too likely that I wouldn't run into another party in a day or 2 with whistle hails or a signal fire.  Granted, there is plenty more I'd like to take, and do take.  I chose quality over quantity, because I'd rather have a good sturdy edge rather than a flimsy disposable razor blade.