Single item per tile?

[requerent]

I think it's better to just trigger the trap with the dropped item- if it's an AOE, interesting, if not, no big deal.

[Holsety]

Now someone will say "use graphics that shows both the trap and the item in the same cell".

"Don't use graphics." 

I think it's better to just trigger the trap with the dropped item- if it's an AOE, interesting, if not, no big deal.

You are the Traphunter. It is your job to hunt down and disarm the sentient traps. However, they have developed the ability to move. To aid you, the Ministry of Sentient Trap Removal has flooded the dungeon with potions. Due to a bureaucratic error the shipment of water potions they were supposed to use has been replaced with random potions from the Ministry of Biological Warfare's storage depots.
The sentient traps dislike having potions piled on top of them, and will move to the least-occupied tiles when nobody's watching. However, triggering a sentient trap will also have disastrous effects on the fragile glass canisters piled on top of it. CAN YOU MAKE IT OUT ALIgod this is stupid. 

[Omnomnom]

Thanks for all the interesting/useful comments. What I'll do from this feedback is reduce the item drops I was planning by making individual items more important, but fewer in number and see if this will allow single drop to work and if not..do something else.

Perhaps a chest icon could denote multiple items on a tile and the player would be expected to stand over the tile to see what's in it? Although I am wary of going too far into iconary (that's not a word...) as in this case there isn't really a literal chest on the tile, it's just some kind of image metaphor for multiple items. So a chest magically appearing might kind of break immersion or make the player think WTF?

Also I was wondering, with single item per tile it is probably best to not encourage the player to drop lots of items in a single place. Is this an argument against weight based inventory as typically to the player might need to dump eg 8 light items in order to pick up a heavy armor?

[kraflab]

I wouldn't use a chest when there isn't a chest.  Something like a pile of different things or a bag or package etc works well usually.

[NON]

What I'll do from this feedback is reduce the item drops I was planning by making individual items more important, but fewer in number and see if this will allow single drop to work and if not..do something else.

Maybe this is completely obvious to everyone, but here's something that helps if you go single item per tile.

Some item types stack - arrows, potions (of the same type), scrolls etc.

In a situation like this:

.....
.[{/.
.{@!.
./[{.
.....

Where
{ [ / = armor, weapons, tools etc
! = Potion of healing
@ = Player, standing on a weapon

If the player drops something (or a monster dies or whatever), check every cell from where the item was dropped, from the closest to the furthest. If a cell with an existing item is encountered before an empty cell, and the dropped item can be stacked with that item, make them stack. So in the example above, if player drops a potion of healing, stack it with the one on the floor. Saves a lot of floor space.

[Holsety]

Also I was wondering, with single item per tile it is probably best to not encourage the player to drop lots of items in a single place. Is this an argument against weight based inventory as typically to the player might need to dump eg 8 light items in order to pick up a heavy armor?

If the player has to dump 8 seperate items in order to pick up one piece of equipment you might want to reconsider the usefulness of your items (though I'm being a dick and taking your example super literally).
Slimy Lichmummy has the weight limit thing going on (it's pile per tile though), but the player can (if he's lucky) get an augmentation that ups the amount of weight he can carry. Failing that, since I don't carry multiples of equipment items, the first things to be considered for dumping are those with the least utility; unidentified potions. If I've IDed scrolls of identify already, then unID'd scrolls are the highest priority for dumping.

Alternatively Forays into Norrendrin just has a backpack that X amount of items can fit in, but equipment is added automatically to the list of weapons/armor you can swap between.

In the end the argument against weight based inventory is weight based inventory itself  
Nobody enjoys having to choose between not picking something up and tossing multiple items in order to pick something up. I think in single item per tile roguelikes you can just have items spill over to adjacent tiles if someone feels the need to unload everything on the spot?