MArcomage

"I play Darkling and I steal X resources"
"Oh no, you son of a... wait, what's X?"
"Well, N is the number of zero cost I have in hand (max 4)"
"Yeah, ok, but what about the X?"
"Dunno, probably it's 42"
"So sick!"

Ha ha, it steals whatever it wants to!

The problem with cards like this is that it does nothing when its opponent-dependent condition isn't met.

Unless you're building a deck against an AI opponent, you're not going to take this card. It's just not attractive enough. It could perhaps be paired with Wildfire gem or other effects that ensure there will be zero-cost cards in the opponent's hand, but I'd want to see this card perform some function even when there are none.

Maybe slap a keyword on it like Horde so it can have a passive function.

Tell that elementalist....

By the way, 1. almost everyone got zero cost supporter commons in his deck 2. the synergies with other cards like elemental storm, consript army and so on are good enough to make such concept worthly.

I would just say to buff it to steal 2 recources per zero cost card...

Elementalist has many advantages that Darkling doesn't.
First, Elementalist affects both your and opponent's hands, so even if your opponent doesn't have any Unliving in deck, you still can discard some Stone atronarchs of Chaos gargoyles from your own hand. Second, it's an uncommon banisher, and Mage and Swift keywords make this card great choice for any facilities+ deck. Third, it's almost as scary for Unliving and Titan decks as Damnation.
With 2N I would at least think about including this card in my deck, but now I agree with DPsycho.

That was actually my point, elementalist ist just that damn powerfull and has only a high potential aganst special decks. Because of this i would say that this card needs a buff to be balanced.

It's a lot better now that it has Horde.

I'd question the additional change that removed the cap, but if your opponent has more than four zero-cost cards in hand, he's not going to be too put out that he lost more resources, resources he doesn't need to play those cards. Everything looks good.