I've always preferred a grid to a list because it allows me to display more items on screen at the same time. It also lends itself to custom corting, so that the thing I want will always be in the same place on the screen when I want it.
List inventories require that we navigate them every time we want to go find something, and that's wasted time. If you added up all the time you spend scrolling through your inventory it would likely be more than the time you would have spent organizing your inventory the one time at the beginning.
So I don't like lists.
Also don't like how DA2 identified Junk items. I don't think the UI should give me that sort of metagame information. I much preferred how NWN handled inventory, where everything was grouped together and it was up to the player to give that collection structure. And this also meant that sometimes the player might misidentify something. And that makes sense. If you haven't yet encountered the quest that relies on this item, you should then have no reason to believe that it is a quest item. You might think it's junk. Or you might think that some junk has a use (like the sheets of vellum in DAO).
I'd also like to see weight limits on inventory. BioWare hasn't used weight limits since they stopped having individual inventories, but weight limits can work with a group inventory, as demonstrated by Wizardry 8.
You make a very good case for a point I'd also like to stress: Let me pack my own bag!
That is essentially the only thing I want from a grid inventory. I do very much like to also have graphical representation of the objects, but you can have that in other forms of inventories as well.
Lists were supposed to be good because they were sortable, filterable and searchable. I hate most implementations I've seen sofar. Because of varying reasons though, and I feel more motivated to talk about what I want, from an inventory.
The first point is whether the inventory should have limitations or not.
I'm very firmly of the opinion, that if the game is not seriously going to make those limitations into a gameplay factor, - then the inventory should be un-limited! The 'as-long-as-you-get-rid-of-all-junk-at-every-trader-you're-going-to-be-able-to-carry-all-and-everything-you-want-just-as-long-as-you're-really-clever-at-playing-tetris' -types of inventory are awful. (The worst I've encountered must be original Dungeon Siege.)
But I do want limitations to be a gameplay factor. And I do want limited inventories. So the question is then, what kind of limitations?
I absolutely don't want a slot or numbers kind of limitation. It's not reasonable or realistic. Likewise, modifications to such a system that , for example, lets you carry the gems in a gem-bag in one slot, are not satisfactory. I want quick access to everything.
A grid-system is a good way to let us pack our own bag. But the grids must then not be a limiting factor. Let the system automatically expand with more pages of grids. If you put something in the last grid of a page, let the system automatically add a new empty page, regardless if the previous is full or not.
You should also be able to push in an object between others, so that all following objects automatically move down a step. For organizing purposes, it would be nice if it's also possible to insert empty slots and line-feeds.
IMO, the inventory should be volume and weight limited. You're not allowed to exceed either. This should be a really easy computer implementation. Each object just has to have a weight (common enough) and a volume. The weight limit can be dependent on the strength of the character. The volume limit can be just an understood general limit, or dependent of the type of bag the character have acquired.
I also think there should be a distinction between two types of inventories: Carried possession, and stashed possessions. This is nothing new. The possibility of stashing items existed already in BG. It would be good though, if it was always possible to check the contents of a stash, to help keep track of what we have, ...and where.