The last time I developed a Boffer LARP system, I began with a set of Positives and Negatives... or, more accurately a continuum of Positive non-negotiables, positive negotiables, negate negotiables, and negative non-negotiables... basically the continuum goes from the ramge pf thins to definitely be a part of the game, through those I'm less opinionated about, and on to those I definitely don't want in the game.
You can find that list here.
I think the main difference in this new system is that magic moves from a non-negotiable positive to a negotiable. Post apocalypse isn't really known for magic, but occasionally psychic powers or mutations appear in the fiction.
I'll probably be looking at the last series of LARP design posts pretty closely as I develop "Can of Beans", reflecting on those ideas in light of the play experiences I've had in the last 15 months since I wrote those posts.
The second post from that series still holds fairly true to my design considerations for this game.
We want ample opportunity for fighting, because that's why we're doing a boffer LARP rather than a parlour LARP. We want influence and status games as the falling society of the past conflicts with the developing societies of the wasteland. We want new players to feel that they aren't completely overshadowed by the veterans, but we do want the veterans to feel like their investment into the game has been worthwhile. Non-human races aren't really a part of most post apocalyptic stories, but if this game is going to be based on the Walkabout setting, then there will definitely be mutants and "spirits who walk in bodies of flesh"... these exotic types will be unusual and it will take some hoops jumped through before a player can access them (they will a be reward and privilege rather than a right), but they will be there. I still don't want "single-strike kills", and I still do want players to gain an advantage from portraying NPC(s) for a session.
The third post still generally holds true with my current thoughts as well. A few hit points per character, where a struck torso counts as 2 hits, and a struck limb counts as either 1 hit or incapacitates the limb for the remainder of the conflict. Armour adds ablative hit points to each location where it is worn. Helmets add an extra hit point to the torso, and may improve the chances of recovery when a character is K/O'd (Thanks to +Klaus Teufel for pointing out that we really want to encourage protective headwear on that original post).
Getting to the fourth post is where a few more subtle changes drift my thoughts for this game away from my thoughts for the game I was developing then. I have some ideas that remain similar, where more advanced weaponry might have some kind of offset in the way of fragility, required skill-set to use or sheer cost.