I would like to see a system where you can set what is supposed to go where, when you do not have it yet. That way when you go loot stuff, it automatically goes where it's supposed to.
In example, you would start with a normal inventory, that you would then specify what goes where.
Here, yellow indicates ammo, green as tools, red as medpacks, and purple as grenades.
Now when you go loot/purchase stuff, it ends up right where it should be.
The positions would save with the loadout.