You just have to master their grenades. Lightning grenades are the only reason I use striker, just make sure you get them on a wall. A flash bang/ shotgun combo is also pretty viable strategy. Besides in the ToO, I find defenders better for crucible. Besides the magnetic grenades, You can put AoL drown right on top of the heavy ammo, or if you have Saint-15, you can put it in a hallway or doorway and have complete control over an area.