@daalnnii Because drawing a card is one of the most expensive mechanics in (almost) all card games.
Look for example at the Cell Phone Zombie. It is a 1/1 that costs 2 brains, but almost all the cards within that cost have around 5 points of stats (2/3, 3/2, 1/4, etc).
IF the card should be reworked (which I still think it shouldn't), I think it should be something like: Grave Buster (2 suns): Summon a 2/2. When played: If a Gravestone is in it's lane, destroy it and destroy this plant.
In this case you get a small plant and the possibility of the same effect (destroy a Gravestone).