Uh oh. You brought up FF XI. You -do- realize that sac pulling was a thing in XI, right? Speed running is nothing new in MMOs and is usually countered by rewarding people for trash kills. Make them drop unique mats. Make them drop tomestones. Make them drop more than 1 bloody gil. Make them have a 1% chance to drop a rare sellable piece of gear. FFS anything.

Also, bringing up FFXI. There was no durability system. You're actively punished for fighting. It doesn't matter if you don't get hit at all, you still lose tons of durability.