While I must agree that Nightstalker grenades are powerful, I must disagree with your opinion over them being "ridiculously powerful". They are very confined to their aoe to do damage in so you have to be pinpoint when dropping them. When a grenade requires that kind of technical use it loses its potency in a lot of cases. Out of the three, the vortex grenade has the best aoe for causing damage and lingers in a spot better than most. Most of the time you'll need to combine it with a poison smoke in oder to get significant results other than keeping enemy players away from a single spot. Next, the issue regarding Showstopper. It is very much weaker than Landfall, not because of its limited usage, but because of its practicality. Landfall may be a onetime use, but it doesn't take away from the super's charge. It is an instant kill the majority of the time, but what makes it far deadlier is that it can be activated [b][i]in the air[/i][/b]. Trying to use a good shotgun to knock out a mid-air Stormcaller about to use Landfall and a grounded Bladedancer preparing for a showstopper have significant difficulties, but it's kinda easy to see which one you'll have a better chance at taking down.