Higher game stage in the harder biomes gives you better loot. There just isn't a loot cap. They tried that with 2.0 and got a lot of unhappy people from it, so it was removed by the next update. As far as magazines go, there isn't really any reason to limit those to game stage. They can already be a challenge to find if you're not perked into certain ones (armor, for example). Having to wait until you're higher level to have a chance to find them would just upset a lot of people for no real reason. If people want to craft things and manage to find magazines quickly, then why not? You still have to spend the time collecting magazines. You could spend the same time building your game stage and be around the same level loot.
Yes I definitely think the current implementation for loot is way better than 2.0's 'loot caps but no biome bonuses' model.
I wasn't proposing tying magazines to loot stage, but having autoshotguns, sniper rifles, SMGs and M-60s, and probably Q5-6 armour, require at least some parts that need a decently high loot stage to find. Or at least find reliably and in quantity.
Being able to craft at a certain quality level is always better than being able to find loot at that level. You get the exact gun/armour set you want, it's repeatable for multiplayer or if you play delete all on death, and you get access to Q6 gear which you can't get from looting. Plus collecting magazines at a decent rate in no way slows up increasing your level, and therefore gamestage and lootstage. This means crafting skill trivialises lootstage.
I'd much rather find that in a mostly forest playthough I'm thinking 'I can craft autoshotguns, but I don't have the parts, so maybe I should prep for a serious expedition into the snow or wasteland to try and find some' than 'yay, 75 magazines, I'm going to make four autoshotguns for everyone'.
Note that I'm a massive crafting fan, and hated the alphas when it was pretty much pointless. I directly campaigned Madmole to allow Q6 crafting, and was pleasantly surprised when that actually became a thing. I don't want crafting to make looting irrelevant, though.