I think something unique would be cool. I feel too many exotics just get a perk that already exists in the game. This does increase the power. However, exotics should be exotic... Do something like the shell hits like normal and explodes, but it creates shrapnel that causes bleed? Reskin poison effects to be red even. Maybe add a hemorrhage effect if enough bleed is applied? I guess that's essentially scorch but would be way cooler and make an exotic feel unique. Also not that much more work if it's just a recolor of existing mechanics. Change the damage values as well.