Hero auto-ability

I think maybe there should be a hero auto ability possible , something that will maybe be in hero settings or on the hero ability page , we've all been there , when we forget or don't activate the Heros ability and they die , because you're preparing and setting down your other troops , so you could have the ability to set the hero to "auto-ability" at a percentage of life the user selects , either say 40% the hero hits 40 percent and it'll auto use your ability if that's where you want to set it auto too, that way the ability at least gets activated guaranteed even if it isn't where you wanted to activated.