Even without the combo, doomhammer represents 16 damage in itself. Dropping 2 hits off of that is still a significant drop in power.
16 damage over four full turns. How many times is that fourth turn even reached? When that fourth turn is reached, does anybody find the card unacceptable?
They already nerfed Doomhammer once by nerfing Rockbiter. A second nerf is pointless.