I've been spending a lot of time in the Gaea Cliffs/Crater/Whirlwind Maze area, trying to steal/win as many unique and hard to get items as possible (99 Dragon Armlets from Blue Dragons, 99 Malboro Tentacles from Malboros, 99 Gigas Armlets from Gigas), but nothing has been as frustrating as trying to get Earth Mallets from Gigas as items left behind in battle.
The drop rate was low to begin with (maybe 10-20%) but I've fought 25 Gigas since Cloud leveled up to 99 and none of them have left behind Earth Mallets (I collected 7 up to that point). So I have a few questions:
1) Does your party's level affect the rate or type of treasure left by some types of monsters?
2) Is there a way to increase the rate at which monsters drop items?
3) Is it even worth it? At least with Malboro Tentacles, you win them every time you kill a Malboro.