Probabilities being probabilities, it may take 5 minutes for one player to farm a card, while it may take another 2 hours. As, the title suggests, it might be a solution to balance those durations a little. I'm not sure which duration is intended, but it starts getting frustrating after a while - that while may vary from player to player. Currently misc items the enemies drop are practically only useful either for sale or to craft equipment that one might no longer need. Some of them may also be fed to pets, but not all. My suggestion is actually not to use the items directly, but to have craftable usable items, which require certain amounts of enemy drops to craft, to temporarily increase the spawn chance of that certain enemy for a certain duration. This way we would at last get consumable craftable items; the misc items would finally become somewhat more useful; and farming for missing cards may happen more focused, instead of getting enemies one no longer needs. There is also the option to increase the drop chance for a card when consuming such items, but that's debatable. Another option would be to make the effect stackable. But those are just some more options, I think it would already be fine without them.