That's intentional for NEXT Brass. You need big brass ones to play it when it can let the runner the fill Archives with agendas or deck you, but if it works then you can get exactly the cards you need.
NEXT Sodium was almost an afterthought, thinking of less-represented metals for the suite. Any trap that can potentially do enough damage to kill on its own is a huge risk, and just setting strength to 0 might not be enough. I was just thinking, though, you could still get some of that "explosion" feel if it was "-> Trash an installed runner card with a cost no greater than X. Trash NEXT Sodium", right? That's still strong, but it's not going to win the game by itself if you have a bunch of rezzed NEXT ice, and you could more easily balance it with cost.