I would rather have nothing in it's place really. For example for the ATMA quest I would prefer being the kill 100 random trash part from the Animus books. The problem is within the design of the FATE system that creates a boring yet stressful enviorment by forcing you to do a really really simple task over and over again yet to be concious while you do it. I can tell that it really requires concentration to do the FATEs. Most farm stuff I can do in an halfsleeping state, not fates due to their race to the goal design.

For open world content I would prefer strong trash groups with a powerful "leader" NM. I think that would finely replace FATEs.