I think that many players want the option to collect some standard categories of items dropped automatically and leave others that they don't need on the flour.
For example: Yesterday, we found a pack of goblins (32 goblins in total) while in a rift in torment 6 and we killed 26 of them. The result was that the whole flour was covered by items/materials/gold/gems etc. We spend almost 5-7 minutes to collect what everyone needed while it takes almost 5-7 minutes to clear the rift (until the guardian).
I think that an extra tool (in option menu i guess) that would give us the choice to collect automatically the category of item preferred (for example: only legendary items, gold and gems without needed to clink on each of them) would be very helpful and give much more speed in the game, especially when you are in fast rifting mode. Of course there should be the option of uncheck the auto picking of potions, since everyone will probably has 1 legendary potion and don't need them.
I think you're on to something. I mean... I sometimes just want to get arcane dust or whatever it is called from the blue items... but good lord in a sea of yellow and in the heat of battle.. I too often just "meh" and keep on going.