The card is still useless since it dosen't have indirect. Place a blocked LOS wall infront of it, and it can not fire.
That is the point of allowing a creature to spend a full action moving it. A mage has placed a wall in front of it and the Hammer is now unable to fire down range. Simply move it and now it is back in play.
That's a difficult thing to balance.
You can't remove all the defensive options from the other player as well, the opponent still needs some room to play aside form "break this thing now"
My only eyebrow raise I get from it is the "corporeal conjuration" forced targeting. Non ethereal attacks get to attempt to hit incorporeal objects in every other scenario in the game..... but whatever.
A fun way to balance Akiro's Hammer would be to play it between zones as if it were a wall.