When the percentages were included on map FATE markers, it was said it would be impossible to keep track of all this information through something akin to a Skywatcher probably because some FATEs can be cleared within seconds, they pop randomly and some don't get touched.

However,

If we could have FATE map markers change in colour to show completion rates that would be better than what we have now, having to check each FATE marker to see if it is viable to join.

Also,

SE, please show us the recommended party numbers we need to complete FATEs (1,2,4,8,+ players) like Timeworn Maps