So you agree with me its probably time to either find a better way to do puzzles in RPG's or just stop doing them altogether. The weight pressure switch puzzle is nothing is not trial and error. I mean until that i didn't even know where to look for the weight of items.
I don't have problem with the puzzles in D:OS (except for button hunts), it's you who do~ I'd say leave it as it is?
the pressure plate, the weight of "difference", discerning the difference is the clue. the normal objects in the area is vase, so there'll be one of them; and the appropriate vase is in the exact room where you need it to be. then the unique items, plated candles (lightest), water bucket (second) and barrel (the heaviest). knowledge of (discerning) different items, different weights.