Since when are you supposed to care about balance?
There is no caring 'about' NPC on the move as written, nor is there anything on the move as written about them having to die while you're healing them.
It says that a NPC *in the PC's care* needs to die to get the +1 Weird, and that means exactly what it says.
Hardholder's people, an Operator's crew, a Hocus's followers, a Chopper's gang, someone a Gunlugger or Battlebabe are protecting, a passenger the Driver is carrying to safety, the person the Brainer is in love with... All of these people count as being in the PCs' care, and you can tell that they are by seeing how the PCs care for them in play.
So yes, it is completelly possible for some playbooks (the ones that get a bunch of people who are both in their care and at risk to begin with) to vault to +3 Weird in seconds. Who cares? First, and most important, you can play this up in the game - the dude just became weird because of a bunch of deaths, so maybe his mind is haunted by ghosts or he sees blood everywhere in his every waking moment. Weird now, wasn't before - why? Gold for the MC.
Second, if we suddenly *do* start caring about balance, a +3 Weird is not that big a deal. For most of the playbooks, it just lets you open your brain with greater success, which is neat but usually of no great significance 'power' wise, and, since the character already burned one get-a-move-from-another-playbook move on getting Touched by Death, the best they can get is a single other neat weird-based move.
Touchstone and Quarantine could go further with this, sure, but not too far. And even if they do, that has some awesome fictional implications. The future of the world, as personified by the Touchstone or Quarantine, has the psychic maelstorm as its integral part.
And if you're already a Weird-based playbook, Touched by Death is completelly superflous.
So... maybe just go put as much pressure on that move as you can instead of worrying what its implications might be.