These tins are gadjets IMO, you will never be able to fit what you need in a tin this size and the least you would need to survive is a knife, fire starter and some container to boil water in. What I believe one should focus on with these tins is not to survive but to make it a few days in the wild. The basics that you need to SURVIVE and most of the stuff you find will only take up space in such a scenario. If you don't have the ability to create some form of shelter with the tin you will find yourself in some serious trouble and you will be in this trouble fast. While some say you one need to find a tree to keep yourself dry I doubt these have ever experienced a night without shelter.
A basic tin for me would have
Fire starting - steel, matches, lens, alcohol tissues
shelter - Plastic bag
Signaling - mirror on the tin, something orange)
1:st aid - pretty much the duct tape + some medical tape for small cuts.
creating a tin that you could survive in the wild for long just isn't realistic. The size of the knife pretty much make it impossible for you to do anything more then cut twigs and prepare food. If you put in a bigger knife, the space won't fit much more. Another problem with a tin is how you would fit a container into it. The tin itself is to small for any reasonable volume of anything and if you need to carry water you are in trouble. The small water carriers that are out there pretty much take up all the space in the tin.
I probably come of as somewhat pessimistic but I do believe we need to get realistic with these tins. If you can't start a afire you are in great trouble, if you can't protect yourself from the elements you are in great trouble, if you can't keep water you are in great trouble, etc. You can survive for a week on water alone but you won't survive for long if you can't get these basics covered within the tin.