you are forgetting when comparing this to golem and spirits that the card's ability has no cost, and can be used whenever you want, sure putting a mark in will lead to at least one of the creatures growing every turn, but more will cause too much draining, while this can be played in mono, also, will get better every turn, but thinking that the opponent is not a dumb AI, he will just wait for an oty or not attack it unless it will die, only real fix i see to this is to give it an active 0 cost ability called "sacrifice" where it gives itself one damage and would then get +2/+0 for his passive.