The inventory system I would like to see would be tied to encumbrance and have a container system.
1. Encumbrance gets calculated by an equation that takes Strength, Endurance, and the load being carried into consideration.
+ A character with high Strength but low Endurance will be able to pick up and carry heavy loads, but, for only short times with rapid Endurance decay.
+ A character with High Endurance will be able to carry loads much longer.
+ Endurance decay slows the character down gradually over time, and auto-replenishes at higher rate with higher Endurance.
+ Endurance decay would require a character to take a break from hiking across the wasteland. Sleep or Wait functions would replenish Endurance.
+ Endurance decay would effect Strength. If you're too tired and worn out, your Strength losses a point, or two, requiring food and rest.
2. Container system would involve a distinction between items worn and carried proper, and items packed away.
+ Standard inventory category tabs would still apply with directory trees to organize item types by subtypes; weapons ->melee, or weapons->energy, armor->light, etc.
+ Items carried and/or worn by the character could have toggles
+ All items not worn, proper carried by character are in backpack, duffle, or some other container that is technically separate, but, seamlessly part of the total inventory list.
Why?
The old pick-up-a-spoon-suddenly-encumbered system is silly.
With encumbrance calculated as described, stacked with a container system, a character could hot-key drop their backpack for combat to move faster, or hide their backpack away before doing something stealthy (the system could tie into stealth and agility checks), and later, come pick up the bag, and load anything found into the bag.
This way a character can drop a huge bunch of non-essential inventory, even cache it away somewhere, in a portable container without worry about finding a container somewhere, and without littering the wasteland with junk because you had to drop some things just to carry some other new thing.
Containers could be map-marker'd as location caches so, a character could fast-travel back to the location to pick up the errant loot.
That's my thoughts on the subject.