This card is absolutely broken, in the same manner cremation is. Both restrict card ideas.
Let's say I wanted to make a really powerful death card, but in order to balance it, I made it cost a ridiculous amount of quanta. Whereas that was fine before, now it isn't possible, as soul catcher makes it too easy to get the quanta. That's the same reason most high cost fire cards wind up being broken, it's just too easy to pay for them. (see: lava golem). The fact that there's nothing to spend the death quanta on now doesn't mean there never will be, and in fact, it actually limits the ability to create cards to spend death quanta on.
The same thing happened with fractal.
When it first came out, there wasn't a whole lot to use with it, your best option being upgraded frogs. But when cards like pheonix and hope came out, suddenly the fact that fractal was broken came to light.
If this card gets added, the following never will be:
Flooding like cards for death
Dissipation shield like cards for death (By the way, dissipation shield + Soul catcher, especially with the new Shrödinger's cat, is hilariously impossible to beat. I pay two entropy for the first cat, trigger six soul catchers, and now you need another 18 damage to get me. Oh, and by the way, I do it six times.)
Pump spells for death
Death cards balanced by cost
I'm saying this right now, there is no way to balance this card. It either generates too much to be fair or too little to be used. I don't want it added at all.