Well i mean they want Sunbreakers to be something you run away from as soon as you see it. And in a lot of cases, that absolutely is possible. I've seen a fair amount of wasted Hammers in Trials.
There are a lot of things that can be tweaked to make it more fair to fight against, but i'd put the instant overshield at the top of that list. No super should be able to save your skin like that and then let you go on to get a bunch of additional kills. Not even popping Radiance lets you survive a firefight.