You counter it by making them panic super. And they only have a few situations where they can get three or more kills, just like Nova Bomb. Blink makes dodging it easier than it should be as well. Even my Warlock can dodge it at least 20% of the time, which is a lot for a super. I can dodge Arc Blade 0% of the time unless it's right at the end of their super, even with Blink. Yes, you can kill Bladedancers during their super, but with their increased mobility, damage resistance, and life regen, it's not that easy. And supers are totally a significant part of the PvP. If used correctly, they are at least 5 kills per game (assuming 2 uses with 2 or 3 kills each). With 6 person teams, that's 30 kills per team per game (if it works out well, probably closer to 20 per game on average). That's a lot.