Mobs dropping a good amount of gil would be my idea for making trash worthwhile.
Maybe implement some sort of mechanic that gives you gil at the end of the a dungeon based on-
1) How many trash mobs you killed
2) How fast you finished the dungeon
3) How many people died/how many times you wiped.
And this wouldnt just be for 50 dungeons. It would be for every dungeon, giving you some incentive to help your leveling friends with their leveling dungeons, or maybe even to DO dungeons on your secondary classes. I dont know about most people, but if it isnt a 50 dungeon, Ive only done it once for story/GC hunting logs. The EXP is atrocious and you'll replace any loot you get quickly. And it should be a significant amount of gil becaue right now there are no ways to MAKE gil. You can earn it, sure, but the amount of gil leaving the economy seems to outweigh the amount coming in, at least after 50.
