There's no reason why a warlock should get an over shield just for hitting with a 50ft melee. It should be changed for a kill. This ability is beyond exploited and should have been nerfed a while ago...
I will gladly trade the entire sunbreaker subclass just to remove blink and flame shield on touch. For you noobs out there my melee kills damn near rival the amount of weapon kills. I really don't need sunbreaker to whoop people....
Edit*
I'd rather it be stronger and last a bit longer on a kill. (Kind of tired of posting this reply on different posts.)
9 dec 2015
I will refrain what's up top. With the storm fist buff, I manged to punch through and still kill a warlock with the shield active.
It's the weakest overshield in the game and you have to specifically choose Flame Shield to get to use it. If the other Scorch perks were actually decent maybe everyone wouldn't run Flame Shield.