Inventory Management in RPGs is nearly always handled in the same manner. There are always those with slots or encumbrance rather than weight, but in my mind the basic formula boils down to the same thing. What does the player have to do to manage his inventory?
When deciding whether to keep or pick up an item, these are the basic steps in most RPG inventory systems, steps that by now are tedious and second nature to most gamers.
Step 1: Is This Item Useful?
Do I need it for a quest? Does it provide stat bonuses better than the items I'm currently using? Does it have situational uses that make it worth keeping around?
If the answer to this question is yes, keep the item in your inventory.
If not, proceed to Step 2.
Step 2: Is this item's gold/weight (or slot) ratio better than any of the items I'm currently keeping around to sell?
Preliminary question => If there is free space in my inventory and using said space impacts my performance in combat/travel, is it worth keeping items?
If yes, how many/much?
Once these are answered, do the comparison (quick mental math usually suffices) and swap the items out or leave the worthless item on the ground.
Now, I've just realized as I was writing it out how much more complicated it looks on paper, but for the human brain, answering these questions is relatively simple. And that is what makes inventory management satisfying for some and tedious for others.
Inventory management, in my opinion, sticks around partly because we can't easily explain away the character never being able to carry stuff around and partly because it was in Dungeons & Dragons. Neither are good reasons.
Most inventory systems allow the character, for ease of gameplay, an unrealistic number of items/amount of weight, so reason one seems silly. Reason two is not a reason to add anything to your game design, whether it's hit points, random dice rolls, or elves who are arrogant.
The solutions I see are:
1. Grudgingly accept that an inventory system is needed in your game and try to improve upon the past standards
2. Throw it out and streamline everything, but not without sacrificing depth of play.
For both, interface design is extremely important (especially number 1 though).
For number one, the key in my mind is making items mean something. To make items mean something, they need to have more than mere commodity value. Instead of a simple value/weight comparison, the player should be motivated by your game to ask more complicated questions like:
Would this item look good decorating my living room? Does this item have value to others in the world to whom I can give it, though not in exchange for monetary reward? Where did this item come from, who made it, and why? You get the idea...
For number two, the question is how to make an RPG without items (or mostly without them) which is more complicated. Upgradeable items that stay with the player the whole game could be one solution, which also neatly adds characterization and narrative dimensions.
Another is to simply make all progression occur through character advancement, and provide a plausible reason that equipment is ignored as a source of power. A third is to have a one-slot inventory system, or one where you can pick up infinite amount of items, or simply limit the number of available items to pick up (this is the route most first person shooters take, i.e. the number keys 1-0 are the number of guns in the game, and once you have a gun you always have it).
To conclude, I think that inventory management can be a fun task for some people and especially can provide a relaxing break from hectic combat, but overall think that inventory and item systems could be much more interesting, given that we seem not to have evolved them much since the D&D days.