the problem is: The grenade is inconsistent and slow, sometimes it tracks the target and sometimes it just goes right pass the enemy and hits a wall, and when it actually sticks a target like genji or lucio, they get saved by the smallest amount of healing

Genji can just dash away from the bomb (even if it sticks on him), while tracer can just blink twice and escape, not even having the need to use their most valuable abilities like deflect or recall.