I liked how in 11 you couldnt leash mobs. It made the game WAY more adventurous. I know this isn't 11 but its a good aspect for the game to have.

1. It helps with SP partys pulling mobs. *with the new leve system i would see SP parties making a comeback,hopefully*
2. Keeps lame exploits from occuring.
3. Adventurer is 'kept on toes'.