I agree with Bobo's post.
In open world games, you need side-grades, not upgrades.
Meaning you're not just finding "higher level" loot, you're finding DIFFERENT loot.
So instead of finding a level 1 pistol that does X-Y damage, and then say a level 5 pistol doing X+5 to Y+5 damage (which basically requires the game to just artificially increase difficulty by making enemies bullet sponges), you find Pistol A, which is super damaging, but very inaccurate. And then Pistol B which is low damage, but super accurate, and then the hundred weapons in between.
So give us 20 different pistols, each with their own pros and cons. All of them balanced and usable, just tuned for different playstyles and character builds. Some more accurate, some more powerful, some with better rates of fire, or reload time, or clip size, etc.
And then with that, give us a decent upgrade system, were we can add sights and modified clips and silencers and all the other various upgrades. So we can take a base gun we like and further focus it to what it's good at, or take a gun and use upgrades to make up for poor stats (adding aiming upgrades to the gun with high damage and bad accuracy).
And with all the "base" weapons, you can then throw in some uniques and special weapons. Guns that are basically modified versions of base guns. Maybe come with higher stats, but have limited upgrade options (or just come with set upgrades that can't be changed). Though really, I like the idea of everything being customized. That way we can also have the choice of picking some weapons on looks.
And the above should basically apply to everything. Weapons, armor, accessories, etc.
And give us the option to customize appearance too.
