On one hand, it was silly carrying 2 sets of armor and 6 weapons and loads of other stuff around, but then I am a bit of a collector and didn't like leaving items behind and I ended up doing the runs from Dungeon to City and back again, carting loot.
I ended up using a saddle bags mod to carry more stuff and that seemed like a good idea. I'd like to see items get removed when you leave them lying around unprotected though. It kind of ruined the fun when you knew you could just drop items anywhere and pick them up at a later date. Big inventories also get very annoying and it would be nice to be forced to only carry a small amount. I'd like to see buyable backpacks as well as saddle bags.
As i said before, I do favour a weight and volume-limited inventory, reasonably mimicking what you'be able to carry in real life. Not only is it more realistic, a good thing, but i believe it to add tactical depth to the game, a great thing. One is forced to choose what and when to carry.
I'm expecting a barrage of criticism from anti-realism forum members. It's just hard to imagine this as a toggable feature - we have to draw the line somewhere - so if this doesn't make it, it won't signal the end of the world. Just a missed opportunity.
I agree about the grid system you mentioned, I've been thinking about this too. I also thought maybe the character could have slots. So they can carry two large weapons on their back, two smaller weapons on their side, and wear one suit of armour. Any extra items would have to be fairly small. This would be very realistic, but maybe too realistic... it pretty much negates the ability to take any extra armour, in addition to the armour you wear.
Pack animals should be the main way of carrying large amounts of loot. Multiple if necessary. It's more realistic that way. No way is someone coming out of a dungeon after fighting through it's monsters/evil npcs with 200-300 pounds of loot & hauling it home on their back without some magical bag that displaces the gear & weight into a pocket dimension.
Character carrying capacity should be limited by the container via a grid system or something similar as well. Size and shape is as much or more of a factor than weight in what you can carry.
I don't get the OCD need to grab every rusty weapon, torch and rock until there's nothing left in the dungeon. It's just not necessary. It shouldn't be encouraged with a flimsy unrealistic system of weight & strength/stamina capacity. The amount of junk that could be carried in previous games was ridiculous. You'd need a 15ft diameter bag to carry it all, and there would be no way to fight while carrying it.
I support ideas like these and other similar ideas I may have missed. I would love something that improves not only the believability, but also the strategic decision making of what and how you should go about obtaining loot. Ideas like these are on the right track in my opinion even if they're not perfect..