DayZ is progression. It's baked into every aspect of the game. From the second you spawn on the beach, you're leveling up. The beauty of it is that no one had to come up with some arbitrary "skill-up" mechanic to give you a sense of accomplishment. Ideas like these would completely spoil the uniqueness of the DayZ experience. You want more friendlies? Make more friends. It's a unique challenge in the DayZ environment, but one that is all the more rewarding because of its difficulty. Put it another way: I don't want to group with you because you spent the morning collecting boar assholes to craft your hunting knife of the asperger's tears. I want to group with you because we trust each other and the game is more fun when you've got my back.