I just tried it. When I heard Arc Blade activate, I ran a good distance away, and as the Bladedancer tried to close the gap, I pumped a full clip of The Last Word into his head, and he died (almost got me though). Heavy Weapon Ammo also works very well against Arc Blade if you happen to have some. One magazine of Pocket Infinity (and two bursts from any other Fusion Rifle) kills Bladedancers and Sunsingers mid-Super too. The Defender Titan's Suppressor Grenade works pretty well too (although it's better for Gunslingers because Bladedancers are very fast).