So. I don’t believe an adventure can have too much treasure in it.
Some folks express concern when an adventure has too many treasures in it. Specifically, too many magic items. Perhaps they see the loot in each dungeon room, or the list at the back of the adventure, and worry that their players are going to become too wealthy or too powerful.
Here is why a ton of loot does not worry me as a designer, or as a GM.
How I see it
There are plenty of reasons why “too much loot” is not a problem at the table.
(1) They never find it. Let’s say your players enter a room and you describe three pieces of furniture. They search two of them, find nothing, get bored, and leave the room. Or they roll badly. Or they get distracted with planning their next move. Or you describe a vicious dog digging in the corner, and they focus on the dog and not what’s buried in the corner. So for any number of reasons, your players may simply not find the loot. This happens all the time.
(2) They never identify it. Let’s say your players find the glowing orb in the hidden drawer. Cool! But none of them have a skill or spell to identify the orb, and they’re not willing to risk experimenting with it. So they put in their backpack and hope to get it identified later. (After the dungeon. Even though it has a cool use that you planned for this dungeon!) And they might just forget they have it entirely. This happens all the time.
(3) They never use it. Let’s say your players find the bone wand, and they identify that it can mind-control any single creature, once a day, for one minute. Cool! But now they can’t decide when to use it. The alert guard? The scheming magician? The angry ghost? And then they make it to the end of the dungeon without using it, and they all shrug and laugh over their indecision about the wand. Oh well! This happens all the time.
(4) They lose it. Let’s say your players find the blessed dagger, and they identify its powers and rules, and they plan to use it when they catch the villain… But then they find a weird stranger, or a magic fountain, or an eldritch altar, and they decide to sacrifice the blessed dagger in exchange for something else of value. This happens all the time.
But what about…?
Even if your players are good about finding, identifying, and using their treasures, it is still well within the GM’s powers to keep things under control. You can remove the item from the dungeon, or you can nerf its powers, or limit its uses, or give the PCs a reason to give up the item, or have someone steal it. The GM has unlimited power, so…
I don’t believe in too much loot.