Losing lot choices through full inventory
As has been addressed in a previous thread to make a lot/pass all feature and similar things, there's currently some problems with the inventory and treasure pool. Right now, you can lot items, then your inv gets filled up, the item drops and you lose it.
And contrary to popular belief, this can also happen if you pass all items in the pool, because new items drop. And the way the game works, it lets untagged items drop first when the treasure pool is full (items without a rare or exclusive tag). That way, tagged items can stay the entire duration of 5min to decide drops. Which, on the one hand, is a good idea. On the other hand, it leads to the aforementioned issue, which can be extremely annoying on certain items. Now some people will, no doubt, argue that those people suck and it's their responsibility to keep checking their treasure pool to pass stuff constantly, but I don't think it has to be like this.
Right now, the FFXI client will only let you lot if you have at least one free inventory space. However, it lets you lot an unlimited number of items, even with only one inventory space. To ease the frustration on players, I think it would be nice if you could only lot as many items as you can hold.
A possible way to do this, that would, coincidentally, also fix the other issue of having items drop to you that will crowd your inventory over the desired limit, would be this:
Make items you lot temporary drop into your inventory.
They don't actually have to be in the inventory, this can be done entirely artificially, just by checking available spaces vs. lot choices. So for example, if someone was sitting at 78/80 inventory, he could only lot two items. These two items would would bring their inventory to 78+2/80 = 80/80. That means he couldn't lot more items or trade with other people or obtain quest rewards, etc. until the drops are sorted out.
There's more ways to fix this issue, this suggestion just came to mind.
Inventory sorting and trading
First of all, please allow satchel and sack to also auto-sort (optional). I know some people use it to store gear and don't want it sorted, so they can grab job-specific gear faster, others however use those for consumables or convenience/quest items, and having it aut-sorted would allow quicker access to those.
Trading items is a major issue at near full inventory. If two people are sitting at 80/80 there's no way for them to trade items, which seems rather pointless. Several ways to address this, one would be the same as with the treasure pool, set the artificial state of the inventory to max(I-X+Y, I)/C, where I is the amount of items currently in the inventory, C the inventory size, X the amount of items traded by party A, Y the amount of items traded by party B. That way, if someone is sitting at 76/80 inventory and has 3 items to receive in the trade pool, their inventory would count as 79/80, and only 1 item from the treasure pool would be allowed to drop. And while at it, a nice and very quick fix would be to not allow someone to put more trade items in the trade box than the other person can receive. Having the trade cancelled and having to redo everything is very tedious.
Also, gil should never count as an item to be traded. Not being able to receive money because your inventory is full is pretty annoying.
Another thing, although that's probably a bit too much to ask for, would be pre-stacking. If you're at 80/80 inventory with 3/12 Gold Beastcoins in one slot, then you should be allowed to lot, trade and steal 9 Gold Beastcoins, until it can't be stacked anymore. This however is not as realistic as the other fixes, so I won't get my hopes up.
Treasure pool conveniences
It was mentioned before in another thread, but since it fits the topic, I'll post it again here.
A feature to lot/pass all items and/or always lot/pass one item. These would have to be set in advance, and could never affect the current treasure pool. This would prevent any kind of ninja-looting completely, so that argument is out of the way.
Select an item in the pool, click it, select "Always pass" or "Always lot" will always pass or lot all future drops of this item, however it will not affect the ones currently in the pool. This would be very useful for large scale runs where you farm triggers, but don't wanna deal with the other useless items the entire time. And the always lot feature would be nice for events like Limbus/Dynamis, or for Empyrean weapons farms, which can take several hours.
I could see something like a tentative pass function to be rather useful. A (seperately marked) pass, that means you won't obtain the item, unless you lot on it. This could be done globally (i.e. automatically apply to all items), or for one item in particular. Alternatively, you could just block your inventory, so you only obtain items you lot on.
Edit: Another thing that I just read here, which I'll mention as well since it fits the topic nicely. Mistakenly lotting/passing happened to everyone because items in the treasure pool shift. My personal suggestion would be to move the cursor along whenever an item is shifted, because the pool is being cleared. If an item moves up, just move the cursor with it, just let it stay on that item. Especially if the lot/pass menu for that item has already been opened.
These features (especially combined with the previous suggestion of temporary inventory filling) would help improve the game's treasure/inventory/trading system immensely and I really hope SE considers something like that.