It should have an exotic perk that's similar to Dragonfly.
[b]Exotic Perk:[/b] Bombgarde: Enemies killed with this weapon explode.
[b]Secondary Perk:[/b] Keep It Blowing: Any enemies slain by Bombgarde explosions will also explode.
This would be a sword with add clearing as its main focus. A way to keep the chained explosions from being too potent would be to make it where the explosions only chain from Bombgarde and not from Keep It Blowing explosions.
I feel like this would be a really fun weapon to play with especially with the recent change to how swords work and how light attacks now cleave through enemies hitting several at once.
It should throw the enemies back first and then explode. Would be a neat effect. You would be literally launching exploding dregs at their captain or thrall at a knight.