Are global ults too slow?

all their ults are global, yet you see them use their ults just to catch people that are just out of their auto attack reach, or just to provide an additional bit of damage into their combo. it takes close to 8 seconds for their ults to reach the other end of the map, in that time a fight can be over with or drag out to a new position. I am thinking maybe there should be an increase in speed for the ults, at least after the first few seconds in the air. Like keep it the same speed for close range use, but after it flies for 2 seconds it doubles the speed. instead of an Ashe arrow reaching top lane in close to 9 seconds it reaches it closer to 5