I don't know if A16 is the best alpha, but I agree there is something really wrong with A19 progression.
I've realized that I now dread starting a new game because the "forced stone age" crap is really annoying and removes all excitement from the first 10-15 hours. And, like the OP, I now avoid looting boxes and chests until I'm level 20 or so, because it feels like a waste otherwise.
Maybe we need additional quality tiers? It's clear 6 tiers is not enough. Increase the max to 10 and spread out the rewards a bit more throughout the progression spectrum. That way, you can still find a level 3 pump shotgun on day 2, and not feel like you leapfrogged to mid-game. Making zombies tougher as the game stage progresses would also help (I mean above and beyond the feral/irradiated variants being introduced. Add larger zombies, zombies that lob explosive projectiles, etc.).