The game isn't supposed to be balanced for multiplayer, as solo is the intended balance point. If they want to add a bit of code to use a separate loot pool when there are more than one players turning in the same quest, that's fine by me. If they did that they could even split the coin and exp as well.
In the first week or two 50 rounds of ammo isn't a total waste, especially if it's the proper caliber. But by the time you're doing T4's and better you probably have the capacity to pump out ammunition of whatever type you need in full stacks, if not boxes. Ammo of the wrong type usually just piles up and eventually gets sold, but with the nerfs to buy and sell prices ammo is hardly worth holding to sell. The people talking about ammo scarcity always confuse me, I've never noticed a shortage of ammo after the first week or two, are ya'll just praying and spraying for body shots of something. Rads can soak up a lot of rounds, even as headshots. Maybe I just melee more than most people, I usually save the guns for hairy spots and horde nights, or when I'm really just trying to rush a PoI ASAP.