Resonator combo would be easy to setup. You run pillars, not lockets, because those help get resonator out & feed the cannon
That said, the cost of 5 is what I assume a stand alone "Destroy target creature" spell should cost. So the question is whether 3/2 pillars are worth redrawing this spell. I'm inclined to agree. Don't think there's a CC shortage to call for this atm
I see a huge difference between CC cards and renewable CC cards. Now, if this card said "Destroy target creature, lose 2 pillars" and thats it, I would be inclined to agree. But having access to renewable CC in an element is often what helps an element stand out and be usable in a variety of decks. Air and owls eye is a good example of this, as is Water and Artic Squid. I could think of a million deck combos I could make with this card being a key piece in them, and adding variety to the pvp metagame is always a good thing.
Essentially what I'm saying is, even if there is no shortage of CC cards, this isn't JUST a CC card; ts an engine that makes way for tons of new strategies, so I wouldn't scrap the idea so quickly.