They are TACTICAL grenades, they set up another action. The swarm grenade is powerful when combined with a shotgun, you can place the seekers in a doorway, wait for the seekers to fade, and blast the sorry fool who follows you in after they fade. Or flank them if that's more your style. The incendiary grenade weakens any enemies inside a zone enough for you to finish them with ease. And you saw the tripmines in the opening level, they packed some power. The grenades probably do the same thing. And since when is an aggressive player only one who gets in close with a lot of armor? I'm saying I move all over the battlefield, getting close and fading back in a quick fashion. Finally,a giant hole in your bladedancer plan: what if "invisibility" is the same as the Stealth Vandals where you could still see an outline and blue static?